I always keep the CD's in case and never lose track of the case's location (two possible: either next to my PC or in the drawer)

I've started to put a label on my disc with the cd key on it with permanent marker... at least I can find it then

I used to keep a list of the CD keys on one cd, but I don't do that much mroe cause I tend not to loose the CD cases as much.
+most of the stuff I do nbow is online so once you enter it you can get it back.

i fond the way -> the wrote cd-keys on the cd :)
copy them in multiples place.
(but starcraft's one is black, so writing wouldn't be seen)
I also emailed myself my cd-keys ;)

I tought i had done the same as you did, but half-life's cd-key is onto the manuel.. Since I had bought the game for the cd-key, that would have been really stupid !!
Try emailling bllizar with all the prof you can find. Else, get the game again, and make sure not to lose the key again ;)

Does your friend has key?

Blizzard is not that bad with remailing keys. (At least that's what I've heard)

Can't you use LAN settings to play directly?

I don't even know where my game is, and of course, I have CDs separated from my CD cases, as those used way too much room. Not so smart idea....

Sent him mine.

There is an option for "spawning" Starcraft cd's. So, if you want to play with your friends, borrow their CD and install a spawn on your computer.

You should only be able to play with the original CD game, but it will allow you to play with your friends. In theory, you should be able to start a 8 players game with only one CD if the person who start the game is the one who own the original CD.

This is true for LAN, I'm not sure if it's so for TCP/IP over the internet, but even if it's only for LAN, you can use Hamachi as I stated numerous times...

LAN = TCP/IP!!! ;)