How to give different contacts their own ringtone?

If it's the same as the droid it's pretty easy, although I dont know why most/all smartphones are limited in this when compared to really old phones. Open the contact, dont select edit instead select options. You should have a ringtone option which will be default, if you select this, it allows you to pick any ringtone you want.

On old phones you could have "groups" of contacts and assign a specific ringtone to each group, there's probably an app for that which I am not aware of.

 

Go to your contacts and select the one you want. Then bring up the menu and select edit. There is an option in there to select ringtone.

 

Select the contact, hit Menu button and choose Edit. Scroll down to Ringtone. Choose Sound to select a sound file from somewhere on your SDCard -or- choose Phone ringtone to choose a ringtone. To add more ringtones to the phone, put compatible sound files in the /media/audio/ringtones folder (via USB connection).