The site
http://distrowatch.com/ has links to all the latest downloads. For a beginner, I would suggest Redhat, Mandriva (formerly Mandrake) or Suse. They are the largest companies and they have the best install programs IMHO. If you can't complete the downloading and burning process, you might want to try purchasing a Linux magazine at your local large book retailer. All the magazines have a free dvd/cd to give away and they always have a distribution.
--Art