Check the Wiki Pages:
http://wiki.radioreference.com/index.php/Motorola_Type_II_SmartZone
This isn't a true repeater operation, each station will support radios that "affiliate" (are within) its operational range -- ie a unit can move from station to station, but a conversation on a station out of your listening range won't be 'repeated' to where you can hear it.
Also find out if your scanner support Control Channel Only Mode so that you only need to program control channels.
You need only to program those stations that you can receive, or plan to receive, while moving around. To tell which station you can recieve, manually program in the control channel(s) and turn off the squelch, you should hear the control frequency. TRS (Trunked Radio Systems) have a shorter range when compared to conventional repeater systems but better penetration, I think the general rule of thumb is about 8 miles.
You must enter TGID (Talkgroup IDs) in order to use the SmartNet/SmartZone features.
If you have a Radio Shack Scanner, there is a discussion on how to possibly program in multiple MOT Trunks into a single bank for this type of application.
This may or may not be all the information, but read the Wiki to get started.