BMW Information

Unofficial BMW	Excellent BMW site containing repair info about all Bimmers. They have a really good discussion board too.
3-series History	<--
E30 M3 the real M3 .com	Good E30 ///M3 site. Some really great photo galleries
E30 M3 Performance	Very technical articles.
Bimmer Roadfly Forum	Good E30 message board.
Strictly eta	Extremely detailed technical specs on all E30s, though the site is focused mainly on the "e" models. There are some tech articles too.

Parts Sites

The Parts Bin	Great place to get OE BMW parts. Good prices and free shipping. I order from the all the time. This site has many other names, like thebenzbin.com and alloembmwparts.com, but they're all the same site.
Importec	Similar stock to the Parts Bin, but prices differ.
AutoWorks Ft. Lauderdale	Used parts.
Bavarian Autosport	Performance and Cosmetic (interior/exterior) parts mainly. Slightly on the expensive side.
Vines	Used parts.
Autohaus Arizona	OE parts.

Repair Guides

Unofficial BMW	Excellent BMW site containing repair info about all Bimmers. Check them out.
MCS Tutorials	Information on replacing shock mounts. Talks about E36 but applicable to all E30s and E46s as well. Well put together. Other tutorials as well.
Understeer .com	Tutorial on swapping out shift levers on an E36. Applicable to E30s as well. Other tutorials as well.
DaveLength Modifications	Detailed walkthroughs of some more advanced mods.
MZ3 .net	A Z3 page, featuring mostly cosmetic and aesthetic upgrades, some of which apply to E30s.
The Driveway Mechanic	E30 Wheel bearing replacement without using any apecial tools (My kind of article!).
ÜberETA	Useful technical info compiled from a message board.

Other

Wesley Blackman's 1967 Mustang	This is my friend's site. It centers around his Ford (gasp!) Mustang, which he and his Dad are restoring from a heap of rusty metal (they insist it's actually a car! :-) But judging by their work on his sister's '66, the "after" pictures promise to be very impressive.
The BMW Racer Page	Misguided Mods - Hilarious!