<DIV>I just went through this recently with a house I bought. They didn't let me know there were already tenants in the attic. We originally bought live traps and caught the critters and released them out of town, then sealed the hole they were entering the house through. That only sort of worked as other squirrels that knew about our attic proceeded to dig there way through the cedar walls of our house. We were going to need to seal the wood again at a cost of about $4000. We looked into a lot of option and finally, reluctantly went with insulated vinyl siding. They have come a long way with siding.
When they were putting up the siding, we found that we also had a wood pecker living in one of the walls of our house & wasps in the attic as well. We have had our siding for about 4 months and have had no problems with critters. We can finally sleep through the night without having the new-born squirrels living in the wall by our bedroom or the ones scampering in the attic waking us up all of the time.
Traps work ok, but they can take a while. The hardest part is sealing your house in a way that will keep them out. Trimming back all of the trees at least 10' from your house helps a lot too.
Good luck!</DIV>