Google Docs&Spreadsheet is a pretty cool app. It allows you to do almost anything you can do with a regular spreadsheet program, but you've got all the advantages of a non-installed program :

• You always have the latest version
• Your sheets are saved automatically
• You can easily add collaborators for your sheets
• Your docs are available anywhere as long as you have internet access

All in all, pretty cool. The latest really cool feature is the one in the image :

Using two special formulas, users can create cells that will update constantly with data or information gleaned from Web searches or Google's finance service.(Lifehacker)

So if you're a financial professional, you can now use Google's Spreadsheets and start working from Starbucks. Wink wink.