I use an Android phone (no thank you, Apple) and am always interested in an application that could help me with my research or studying. Unfortunately, the Android marketplace is cluttered with irrelevant applications, making finding useful applications difficult.
The following applications are presented as a summary of what I use. Certainly there are more out there (please tell me!) and more are created every day, and I look forward to using these applications in the future:
Astrid Tasks: Every morning as I'm walking into the building, I fill out my task list of things to do for the day. I don't need anything fancy - I just need an application that is quick, easy, and simple. Astrid is fantastic for putting together this list and for prioritizing my experiments and work. Plus, it's got a handy widget (if you're into widgets, that is). I would highly recommend this application for those who like to keep lists.
GoogleDocs: If you use Google for composing, sharing, or viewing documents, this application is fantastic because it will sync your computer and your phone to view the same documents. Additionally, if you've got a big enough screen, it's not too horrible to actually compose in these documents. I don't use this too often, but it's convenient when I've got a document to get on my phone and my Dropbox happens to be full (see below).
Doodle: Have you ever tried to schedule a meeting with faculty? How about with multiple faculty? Needless to say, it is a nightmare: herding cats as many would say. Doodle attempts to make this a little bit easier by creating a spreadsheet which participants can then check off for their ability. That one magical time spot that everyone checks is then the meeting time. Doodle comes with several options for creating an event and then adding participants. In my department, these things are really the best way to make sure that a meeting is really going to happen.
Dropbox: If you're not already on Dropbox, seriously, sign up for it. This program is the most useful thing I have every used. Once installed on a few computers and on your phone, a folder is created - your Dropbox. It acts just like a normal system folder and can be manipulated just like one too. The great thing is that anything that is in your Dropbox can be accessed on any computer that has Dropbox installed and you can also access your files online. This is so much better than carrying around a flash drive, and the syncing is instantaneous. I could not recommend this program more.
handyCalc: Usually, I'll use my crappy old calculator from high school to do the simple arithmetic needed for my experiments and notebook. When I'm at my computer and can't find my calculator, I use handyCalc, mainly because I find it much easier to use than the standard calculator that came with my phone. There are multiple iterations of calculators out there - from simple to mind-bogglingly complex. This program will solve equations, create graphs, and perform simple addition and subtraction. It works and I like it.
LinkedIn: At a recent conference, I learned the importance of LinkedIn. The seminar speaker asked everyone in the room to raise their hand if they were a member of LinkedIn. I was the only person not to raise my hand. LinkedIn is a Facebook for professionals - it can be helpful if you're looking for a job or want to make some contacts to look for a job in the future. Being able to use it on my phone is convenient, too.
Pulse: I like to read the news on my phone when I can't access a computer. The best app I've found for this is the Pulse reader app. Using this program, you can view tiles containing the top headlines from various websites, including numerous science-slanting websites. The handy swipe-to-change-story feature is nice, and the entire interface is easy-to-use. I also like using this while I'm walking because it's easy to pull up a short story that I can finish quickly and make myself feel like I accomplished something.
QuickOffice: I'm not a big fan of paid applications - I am a poor graduate student after all. QuickOffice came preinstalled with my phone, and I must say that I am quite impressed with it. It has the same features as the Microsoft Office suite (I can even view my PowerPoint slides on my phone!) and is really easy to use. If you're not up for shelling out $15 (!), you can always opt for the Google Docs app, which I think is almost just as good, and you can't beat the price...
Google Reader: I use Google Reader religiously for keeping up on journal articles. This handy little app presents my RSS feed conveniently and in my pocket so that I can keep up on my papers that I need to read. Since I can't access the actual papers on my phone, I star the articles of interest and download on my computer when I'm connected to my university's network.
The Weather Channel: I work in a lab with no windows. Most of the time, I can't tell is there's a tornado outside or a beautiful sunny day. Sometimes, that's for the best because then I'm not tempted to leave my benchtop and wander outside. When I do have to go outside, however, it's nice to know the weather, and the Weather Channel app is convenient for quickly checking the weather. Tons of functionality are included, such as animated weather maps. There are a lot of weather applications out there, but I find this to be the most useful.
WTFSIMFD: Hands down, my favorite food app. WTFSIMFD provides you with a recipes that you should eat. The app has a potty mouth, but it's amusing and endearing at the same time. It also gives great recipes, you know, for when you're not in the lab or studying...
Just a roundup of what I find useful as a student and a scientist. Maybe a followup post will be necessary when I find even more useful apps...