Repeat after me: "There is nothing wrong with making money for something I enjoy."
None of us are in this for the money, although as I said, there are dozens of dollars to be made in webcomics. Literally dozens. So why not get paid a couple of bucks for doing something you love?
Some options currently gaining popularity
Check out both Project Wonderful and SpeechBubble, for both selling AND buying ad space.
CPM (pay-per-impression, or "cost per thousand") ad companies
CPM companies may be your best bet for monetizing. The amount of money you earn is directly related to how many readers you have, and on how many pages they view when they visit your site.
If your site gets 10,000 or more unique visitors a month (and if not, see the section before this), apply to Casale at the link below.
Accept donations
If you haven't already, open up a Paypal account so you can put a donation button on your site. Many webcomics survive off of donations alone.
Syndication
There are a few webcomic strips (Partially Clips for one) that have been syndicated into newspapers, whether alternative papers or standard newspapers. If your webcomic fits the mood of a certain paper, you may as well contact them and find out if they accept submissions. The worst that can happen is that they can say no.
Affiliate Networks
Once you join these networks you can go through thier lists of advertisers and apply to specific programs. These ads pay when someone purchases goods or services, or when they fill out a "lead" form.
Sell ads
You can do this a couple of different ways. On your own (probably usuing a program like PHPAdsNew), or through an agency.
One popular agency we've used is Adbrite. Adbrite gets a 30% fee, and you keep the rest. You can either set your own ad prices or let them manage that for you. If no one has purchased ads for your site, you can set your preferences to have "network ads" run.
Pay-Per-Click networks
While some new Pay Per Click networks are beginning to make news, we've not tried the new ones yet. As soon as we get a chance to check them out, I'll post about them here.
One Pay Per Click we have used is Kanoodle. Kanoodle is geared more toward high-text-content websites, but they may be worth a try for you. We've had some success with them in the past, and may end up running their ads again in the future.
Subscription
You can always charge a fee for people to view your comic, or do like Rob Balder and Steve Abrams do--Let people read your comic for free but provide an optional subscription structure that lets readers surf your site ad-free and maybe get some additional content. I have no idea how to set this up on a practical level, but as soon as I know, I'll post about it here. There is always the option of using Webcomics Nation, which will let you charge a subscription fee. (We talked about them back in the hosting section, remember?)
Last, but not least, you can apply to join an existing subscription-service site like Keenspot or Modern Tales. To be honest, though, if you're just starting out, the odds are against you. Sure, it could happen, but the vast majority of comics accepted to these sites are well-established, which is why I didn't mention them in the hosting section earlier.
