For the location of the equipment, I believe it is on the top...
To see the differences between the different types of memberships, check this out: http://s4gru.com/index.php?/topic/1195-information-about-s4gru-sponsorship-levels-and-how-to-become-a-sponsor/
As for types of maps, you would have access to all of the sprint sites they have information on and where it is in the NV phase. If you would like information on clearwire sites (band 26/41) you will need to become a premier sponsor (totally worth it!)
If you're unsure on how far you would like to go, start off with a small donation and you can be a sponsor for 6 months. If you decide you wish to become a premier sponsor, you can then donate some more. Hope that helps.