True there are no PSL's for Colts tickets but you can certainly sell your ticket rights.To be able to avoid waiting in line you can buy the rights. I have done it many times. Of course if you want you can just let the tickets lapse but why not make a few dollars?
You are selling next years rights not this seasons tickets so yes you keep your tickets for the rest of this season, Transfer takes place at the end of this month and the new STH will get an account set up then. I have sold 4 of our 8 so far. FWIW I don't use the Colts site because they charge too much in commissions