Perhaps the only thing harder to find than good comics are good websites devoted to comics. If you don't know where to look, that is. Following are some of my favorite comics-related websites, divided by subject matter.
News, Reviews, and Criticism
The Comics Journal - Originally a monthly magazine, the Comics Journal is now an annual publication and a regularly updated website. Since the early '80s the Comics Journal has been the leading (if somewhat controversial) voice of American comics criticism. The website contains not only news and criticism, but also links to a dozen or so critically astute blogs sponsored by the magazine.
The Graphic Novel Reporter - A fine alternative to the Comics Journal if you're looking for something a bit less, well, combative. The Graphic Novel Reporter features interviews, reviews, and criticism. One feature I appreciate is that it divides its reviews into sections: adult fiction, adult nonfiction, teens, and kids.
The Daily Crosshatch - A sort of comics magazine in the blog format, this website features reviews of indy comics and interviews with the writers and artists who create them.
The Blog Flume - Another blog-style review and criticism site for indy comics.
The Hooded Utilitarian - A somewhat contentious (à la the Comics Journal) blog of comics criticism.
The website of Dr. Rocco Versaci - Looking for something a little more scholarly? Professor Versaci's website is a good place to start. He's been teaching comics as literature to students since 1997, and his website is very illuminating.
Online Comic Strips
The Webcomic Overlook - A guide to online comic strips.
Barnacle Press - Not webcomics, actually, but scans of very old newspaper comics now in the public domain (or presumably so, anyway). The artistry on most of these strips is amazing. A far cry from today's newspaper funnypages.
Hark! A Vagrant by Kate Beaton - My absolute favorite webcomic. Kate Beaton is so, so funny, and no one can match the way she illustrates historical (or literary) personages acting goofy. If you visit this site you will be hooked. I guarantee it.
Sinfest by Tatsuya Ishida - This one can get a bit racy, but only in a PG-13 kind of way.
Achewood by Chris Onstad - Though I'm tempted to call this one a cult favorite, it's so insanely popular that it only seems like a cult favorite.
American Elf by James Kochalka - An Internet staple. James's daily life boiled down to four comic strip panels.
Cat and Girl by Dorothy Gambrell - A very charming comic.
Exploding Dog by Sam Brown - Hard to describe. You'd just have to visit it.
Webcomics by Scott McCloud - Included here since Mr. McCloud is sort of the elder statesman of online comics.