|MadSci Network: Astronomy|
Holli- whether cosmology is a good career for you depends on your skills and interests. Cosmology is usually considered to be a branch of astronomy or physics, and answers to a lot of your questions (where would I work, how much would I make) are in the brochure A New Universe to Explore: Careers in Astronomy, put out by the American Astronomical Society.
You have to really want to do astronomy for a living, or it's probably not worth the personal (many years in graduate school) and financial (even top astronomers don't make huge sums of money) costs. Also, it's important to be self-motivated and patient; in research there is no one telling you what to do every minute of every day, and progress can take a while. But if you are really interested in understanding the universe, there is no better job than to be able to go work every day and try to figure it out.
For more information, feel free to e-mail me, or see the Astronomy Career section of the Ask the Space Scientist site.
Try the links in the MadSci Library for more information on Astronomy.