I personally LOVE Dropbox and here's a great review of this cloud storage tool. You can share files easily and files are automatically updated as you work on them from any computer. I give this my HIGHEST recommendation.
Free cloud storage with Copy--works similar to Dropbox -- free and 15 GB of storage. (I use Dropbox and see no need to change, but this has an app that you can install on any device and, apparently, is not in conflict with Dropbox). Might be worth a book.
Tag cloud creators--great summary all on one place (e.g., Wordle). I have used several and find them pretty straightforward to use. (Note Tagful will only give 1 month free--so use the 'free' sources.)
Notability is an iPad app for note taking that allows collaborative (or not) notetaking with sharing options. Plus it works with Dropbox (cloud storage)
VocabGrabber is word cloud resource that allow you to enter text and then it automatically generates a thesaurus of word meanings. Looks interesting for helping students with difficult vocabulary.
Audacity Tip Sheet for Students--succinct. If your students use Audacity to record sound (for podcasts), this is helpful. Remember Audcity files have to be converted into mp3. Most students struggle with finding LAME, which only has to be clicked on once.Obviously, this is for PCs and not Mac.
I just used this site/download with an iPod project in my classroom. It is probably the most important site I have found in years. The primes is simple and there are probably pleanty of other sites like it but.... WOW.
You can drop your files into the dropbox and they are saved to the "cloud". Then amazingly they are on every computer ( or iPod) you have linked to the account. I entered my account info on the student iPods and made a folder for each student, when they were done with a project, they saved it to the folder. The great thing about this was i could access their assigment from anywhere, my home computer, my iPhone, another iPod in the class, the smart board...it was limitless, I could share it with anyone, no matter where I was...how powerful. I also made a folder of "mrs. Kondrick's resources" where I put videos, audios, assignments, rubrics etc, and then they could watch them/use them at their own pace ( so ethnic that works well with our individualized daily 5 reading block.