Not really, some filter add-ons for PS let you touch the image up to make it nicer, like the 'Pixel Plugin' but in general you will only lose quality. The only image that won't lose quality despite what size it is is a vector, and then it has to be a true vector.
thats helpful^ lol. Alien-Skin-Blowup is the one i use, doesnt really come useful as i neve ruse it lol.
buy the name changing item or pm one of the admins. i think they do it if you have less then like 50 posts or something