Re: Sending files
The easiest way is to simply use Apple's "Bluetooth File Exchange" to send a file to your phone. You can also use an OS X app called "PhoneAgent".
The only issue you may have with the Bluetooth File Exhange utility, is in Jaguar, bluetooth connections seem to stay open for over a minute after the file exchange has compleated, preventing you from sending additioinal files. This issue has been cleared up in Panther.
On your phone you just have to make sure Bluetooth is turned on. The first time you send a file, you may have to pair your phone with the computer.