Google Spreadsheets, Google Calendar
Google has released two applications that are very interesting. I’ve played around with both. Google spreadsheets is the most recent release. You can import XLS or csv files into Google Spreadsheets and then you can use formulas and sorts on the spreadsheets just like in a desktop spreadsheet program. The cool thing about online spreadsheets is you can share them with someone else. You can allow the person you are sharing it with to either just view the spreadsheet, or you can allow them to edit the spreadsheet.
At the present time, Google Spreadsheets are not compatible with the Apple Safari browser. Mozilla Firefox is the preferred alternative on Mac OS X.
Google Calendar is a great online tool. The upside of Google Calendar is that they just recently made it compatible with Apple Safari. As with any calendar including iCal you can add events and set reminders. You can have recurring events. You can share your calendar with others. Google has also added some web services for Calendar. You can embed a calendar into your own website, and you can allow users to add events to your website calendar.
Google has been very busy this past year and is releasing some great web tools.