Mizumoto auto parts (or something like that) on eBay has proven to be a reliable source for Aisin (they make a huge amount of parts for Toyota and you'll find their name actually stamped on many right by the Toyota name) and NPR (good quality OEM replacements).
Champion Toyota out of Texes is pretty easy to deal with and often offer better retail prices on "Genuine Toyota" parts than many local dealerships.
www.toyotaworld.com
For aftermarket IC couplers, ICs, silicone vacuum tubing and such I really like SiliconeIntakes.
www.siliconeintakes.com They're located in southern CO so they manage to get parts to me VERY quickly too!
Do note that a lot of interior components are either discontinued or VERY expensive new.