Its time for a handy guide to info on climate change and global warming.
If you only have time to read one page, then the Wikipedia page Global Warming is a good place to start (but see the wiki-caveat at the end of this post) and to follow the links.
If you have lots of time and are prepared to read technical language and want lots of pointers to the literature, then the IPCC 2001 report (TAR) is unquestionably the place to go. Or you can read just the Summary for Policymakers or the in-between Technical Summary. The TAR has ageed well, and remains a good reference for most things, although the fourth (AR4) report is now in draft.
[Update: nowadays you'll likely prefer the AR5, its SPM, or the TS.]
This is a good place to point out that by "global warming" *I* mean the basic science, which is in IPCC parlance the WGI stuff. I don't mean the effects or adaption or the economics stuff that people spend so long arguing about (which are WGII and III stuff; if you don't know what WGI/II/III are, follow the IPCC link above). The ever-thoughtful Michael Tobis had a nice post addressing some of this in the early days of RealClimate. If I fling around the word "consensus" here and you wonder what I mean by that, then Just what is this Consensus anyway? will tell you.
Most of the links will tell you about how the climate is changing and suchlike. Few will explain to you the underlying mechanisms. A good (though now dated, to 1997) ref for this is Climate change: some basics.
Two areas that have seen a lot of attention since the TAR deserve special mention: tropospheric temperature trends; and the long-term temperature record. For the first, there was a puzzle about disparities between atmospheric and surface temperature trends. This now seems to be resolved in favour of the surface, models and std.global-warming: the old satellite temperature record was wrong (RC) and the supporting radiosonde (balloon) record was probably wrong too (RC again); the wiki [[Satellite temperature measurements]] is good too. The second is less resolved: [[Temperature record of the past 1000 years]]; Dummies guide to the latest Hockey Stick controversy, but happily the TAR take-home-message ("the increase in temperature in the 20th century is likely to have been the largest of any century during the past 1,000 years. It is also likely that, in the Northern Hemisphere, the 1990s was the warmest decade and 1998 the warmest year") remains valid in all reconstructions subsequently published. In a token piece of balance, and as a terrible warning of what happens if you obsess too much over trivia, I'll point you to www.climateaudit.org for the dark side.
If you want to *discuss* climate change, then the balkanised landscape of blogs is a poor place: the newsgroup sci.environment is better. James Annan explicitly directs people there rather than put comments on his blog, and thats a pretty sensible attitude. There are a variety of climate-type blogs I read linked on my masthead; RealClimate gets a special mention.
If you've got this far, you may be wondering "OK, thats the std view, but what about the other side?". It appears to be a fair question, but in fact isn't. As far as I'm concerned, thats the balance-of-science view (see here; for my look at the greeny side, try this; or the dark side). If you want the non-science view, you won't have any trouble: people ranting about climate change are all over the web (err, I'm over-egging the pudding there, of course. It is still (just about) possible to be scientifically respectable and doubt the consensus view. But the numbers of such are small, and shrinking (Lindzen has been rather quiet recently)). The wiki GW page will find you enough links, and various of the pages: [[List of scientists opposing global_warming consensus]] or [[Global warming controversy]] will find you more, if you want.
There are various GW myths that I've analysed: see 1 and 2 for some.
And thats it for this post. There's just time for a...
Wiki-Caveat: Most of the wikipedia pages about climate change are currently sane and have been stable for a fair while. That doesn't mean that they will still be sane when you read this post, but I'm hopeful. If you're interested in poking around in their history, click the little tab at the top marked "history". If you want to ask questions about them, click "discussion". And if you just know they are wrong or incomplete, then there is a little tab marked "edit". But bear in mind that people watch them; if you try to fill them with septic trash it will get taken out again.