do blackberry's keep email on the device until you delete them? My current phone holds my emails for a day or two and then deletes them from my phone. I hate that, can't wait for the 8900 so I can join the BB world
You can set how long to keep emails and messages for (15 days, 30 days, 2 months, etc). As long as there is enough memory to run applications and whatnot the phone won't delete them before the specified time.
When 15 days or 30 days passes and your messages are purged from your BB, it is not actually 'deleted' the same way it would be deleted if you explictly delete them. They will still be around on your server unlike an explicit delete.