Homer, if you mean outputs for speakers that will be mounted on the side walls, any 5.1, 6.1 or 7.1 receiver will do the trick. Typically Dolby labs recommends mounting the "surround speakers" on the side walls in a 5.1 system, however most people I know have theirs mounted on the back wall. If you go 6.1, you add a single speaker in the center of the back wall, and 7.1 adds two speakers on the back wall.
Just look for any current Home Theater or Surround sound reciever. If it has Dolby Digital 5.1, DTS, Dobly EX, etc., it has, by default, "side speaker" outputs. They are listed on the receiver as "surround L" and "surround R". If it is a 6.1 or 7.1 channel reciever, it probably also list them as "surround L&R" and list the rear wall speaker outputs as "back L and back R" or "Rear L and Rear R".
If you are looking for a surround sound/HT receiver that supports speakers in the front (L, R, Center), sides (surround) and back (rear wall), go for any 7.1 channel receiver. It will, by default, have outputs for "side" speakers.
Enjoy,
TIC
