How to add a sign up button on home page for a multisite set up and Anti-Splog

Hi

We are setting up a multisite network using the pro site plugin and anti splog, just wondering is there a way to add a sign up button on our home page whilst using the anti splog plugin that changes the signup url every 24hrs.

If so any help here would be great.

and examples of how to do it.

Thanks

Jamie