it all depends on the phone, try looking on google for websites about your phone and hacks or tricks, it might allow you to download ringtones for free, change logos, add and remove names and such easily. it all depends on the phone and such
My Nokia 7210 and 6310 i have a cable for...
Basically, you can use the phone as a modem
Backup phone book/msgs
edit things on the computer rather than computer
upload logo's and ringtones
and lastly hack the network locks.