The Breifing Room - Website of the Legendary GIBit. Its a little known but it is "the largest collection of C&C, TA, TAK, and a bunch of other games files". A truely awesome sitle.
XCC - The homepage of Olaf van der Spek. You can download all the XCC Programs there, and It has a cool message board you ask XCC/C&C questions on.
Tiberian Sun Factory - ReaprZero's Tiberium Sun Editing site. Although it hasnt been updated in forever, It has the largest collection of voxels around.
Red Alert 2 Factory - After TSF's bomb, Reapr opened. Now, This site has bombed also, but dont worry, Version 2.0 of his site is opening, and it will be A LOT better, one reason is he hired me :D. Expected Opening: March, 2001.
C&C Afterglow - The Post Release Devlopment Center, this is a great site if you are looking for myrid of editing information. Most of the TS editing info can be used for RA2 editing,
Final Sun - The webpage of the best TS and RA2 map editors around. If you need to make maps, go here.
RPG Maker Pavilion - The best (and only) Fansite for the PSX RPG Maker. Great info, great boards, this stite has everything you RPG Makers need.
Alien Audio - A pretty cool site, I got pretty sweet car stereo there for a pretty cheap price. Check it out.