Yes they have online collaboration tools. They used to be free, but now it's a paid service. The good news is that it's $5/month.
And I agree with omeguy! When you're trying to break in you have to obey the rules, even the ones you don't agree with, but once you've established yourself you can get away with a lot more.
Celtx is great. I've used it for years and any problems I've ever had are usually resolved by the next version release.