A godsend for the organizationally challenged, Evernote lets you type and synchronize notes, photos and voice memos from your iPhone to the Web. Everything can be accessed later from the Evernote application or the Evernote website, where the company offers a free desktop client for Apple and Windows PCs. Notes are searchable and tagable, and Evernote even tries to recognize and index text in photo snapshots. There's no better application to keep class notes on hand at all times. (Evernote, free)