That is beautiful, Shannon! It looks like Escobaria vivipara or something similar. Neil, if you're looking for one, some of the better-regarded mail order cactus nurseries are
Mesa Garden and
Miles 2 Go. Be careful, cacti can be just as addictive as orchids!
---------- Post added at 04:43 PM ---------- Previous post was at 04:22 PM ----------
Oh, and your pretty orange-flowered one looks like it could be Parodia (formerly Notocactus) haselbergii. Lovely little plants!
BTW,
cactiguide.com is an excellent cactus site with a large image library, generally up-to-date taxonomic info, and a very helpful forum. Most of what little I know about Cactaceae comes from there-- the forum is especially great for IDs and culture advice.