I've had good success with all of these guys on ebay:
http://shop.ebay.com/gamedaylegends/m.h ... ksid=p3686http://stores.ebay.com/ONtheCOURTSports ... lia?_rdc=1http://stores.ebay.com/Press-Pass-Colle ... ery?_rdc=1http://stores.ebay.com/Hollywood-Collec ... 4340.l2563I can't find them, but there is also an ebay store called Cardboard Legends that has a ton of Lakers stuff.
This is a great web site to keep track of what's going on with signings:
http://www.signingshotline.com/fre/fre_ ... emorabiliaThese guys have been a staple for me in building my collection:
http://www.halloffamesports.com/They have a signing set up with Magic so you can pick what you'd like him to sign and mail it. I can't recommend these guys enough.
A note on ebay: There are lots of good sellers, but also a lot of crooks. Don't even think about buying anything that isn't at least authenticated. And even then, it's not a guarantee. I learned this lesson the hard way.
If you can buy anything from Upper Deck, Steiner, Schwartz, Mounted Memories, do it. It's way more expensive, but it's worth it because there's no doubt the stuff is legit. Otherwise, try to either get it signed yourself through mail order or stuff that's authenticated by PSA/DNA or Spence. GAI is decent, but I bought a Patrick Ewing ball they verified that is clearly a fake.
I can't stress this enough: unless you are really familiar with a guy's signature, do not buy anything that is not authentic or verified.