glassyeyes.com all the way. i think it might have even been a neatorama article years ago. cheap, online, reviewed. i have like 15 some odd pairs of awesome glasses now from that site [which is just a blog that links to and reviews sites that sell glasses with lenses online] and have been very happy with all of them.
only problem is you cant try them on, but after a quick trip to any eyeglasses hut in the mall, you can get a good gist of what you want and even get frame dimensions for exact replication.
good times.