Don't know about the already made insoles really, but just wanted to tell you that orthotics made for running/walking are different from orthotics made specifically for cycling. So, if you are having issues with your feet when cycling and have really strange feet, i.e. high, high arches, you might want to get orthotics made for cycling.

I have feet problems but not ever from cycling, only when I run/play tennis, etc. So I really don't need a special orthotic or fancy insert for my cycling shoes.