offer a content site and advertise via affiliate programs. It's a ton of work, but other than setting up an online store and paying a ton in pay-per-click campaigns in a hope to not lose your shirt, it's the easiest thing. (no, not the classic planetarion banner-ad model..those NEVER worked)
Also, check out sites like:
www.marketingexperiments.com <--has a free newsletter but the paid content will be what you're looking for once you're "in business" (shameless plug)
www.webmasterworld.com <--Great forums for all kinds of web-related stuff
www.marketingsherpa.com <--another great newsletter.
http://www.associateprograms.com/sea...wsletter.shtml <--Affiliate programs site. lots of handy information about that stuff.
http://iafma.org/forums.html <---affiliate organization..helpful people as well.
There is no magic way to make money, it tends to be expensive to get started, and a ton of work.
You could always try doing a review or specialized information site. The problem, of course, is that "it's all been done" so you need to figure out your value proposition and go from there...that being what you have that no one else does. Build your idea around that and you're going somewhere.