Microsoft used to have a white paper on it here: http://www.microsoft.com/sql/techinfo/whitepapers/migrate-crystal-to-reporting-services.mspx

But its gone now. I may have a copy sitting around on an old laptop...

I've done quite a few Crystal to SSRS conversions. It's painful and takes a lot of time!

I encourage you to have a look at http://www.CrystalConversions.com and make your own conclusions about whether its worth doing manually,

or pay a small amount for it to be done for you.