If you've got time on your hands and you aren't trying to run a live exchange, it's not that hard to write something that checks into Yahoo! Sports, or the madduxsports lines or linesmaker.com and scrapes the scores and lines every few hours.

Or you can try OddsMiner.com, I don't know what their pricing is like but if it's a small project it sounds like they're flexible.

Thanks for the sources, will look into them. OddsMiner could be useful.

My first reaction was to scrape data, but as it's for a fantasy league, which runs for at least an entire season, there is a good chance the scraper will break a few times during the season, potentially requiring a re-write. This isn't ideal if on the week it breaks I don't have time to update the code.

I scrape ESPN data for this tool:

http://recaps.raptorsrepublic.com/

Generates recaps/box-scores that are used by....yup, ESPN TrueHoop bloggers.

What about outsourcing it? Perhaps using MechanicalTurk to have people enter game data.

It'll cost you some money, but depending on how much you value your time, it could still be a bargain.

But is that legal to scrape data?

checkout using YQL to pull data from Yahoo! Sports.