Something else too, to think about.
There are some websites you can write for that pay money for writing blog entries, essays, etc. And some members at AW do write for these. There are many that have people around the world bidding on the jobs, and the lowest bidder gets the job. I recommend against this practice because ultimately you're going to write a 1,500 word article for $5.
That's ridiculous pay for writing.
If you're serious about the whole freelance writing thing, do what others in this thread have suggested already. I'll reiterate.
Go to the news stand and pick out magazines you'd like to write for. Read them and see what the articles are like.
Check Writers Market 2009 for their submission guidelines. Many of these magazines are closed to freelancers, and they sometimes won't say that on their websites. For instance, Entertainment Weekly is closed to freelancers.
If you have a topic in mind for a particular magazine, you write the query letter which is a brief description of the article, its length, its audience, and your writing credits. See the AW forum "Query Letter Hell" on how to write effective queries.
Submit to the magazine and wait.
Magazine article submissions are highly competitive. Magazines get jillions of queries and only publish certain amounts of articles per issue. Oftentimes they favor the writers who already write for them.
But if you do break in, payment, for an average size, 1,500 word to 2,000 word article could be between $200 and $500, maybe more, depending on the magazine. Writers Market will list the rates paid. The individual magazines' websites will not.
Once your query is accepted, you have to produce the article. They'll give you a deadline, and they expect professional quality. If you deliver less than what they expect, although they will edit it, they may never use you again.
However, if they like you, they'll contact you with articles they'll want you to write in the future.