Reviving this thread from the dead-
Just did a remote start on my 2011 Prius using the DEI "remote-start-ready" configuration. With the T-harness, it was seriously a piece of cake - just connect the harness to the obdII port, hook-up 5 wires and you're done.
However, if your car is not remote-start-ready, then the Compustar FT-6200s brain with the idatalink blade-al module may be a good route, since the bypass unit slides into the remote starter's brain - thereby eliminating a number of wires.
As previously stated, the12volt is a good resource. Bulldog security also provides free wiring diagrams on their website. Lastly, audiovox's tech section provides diagrams as well - and probably the best ones. Just be advised that xpresskit's diagrams does not show all of the wires that need to be connected for the remote starter brain (it usually shows 5 wires that need to be connected from the remote starter).