I was able to migrate Crystal 8.5 reports directly to Crystal XI with few problems, and I suspect you might be able to do that with 2008. The best way is to just try to open one of your 8.5 reports in Crystal 2008. If it opens, you can save it in the 2008 format without having to go through any intermediate steps.
One thing you need to be aware of, though: if any manual changes were made to the SQL in Crystal 8.5, that report will not migrate cleanly and will probably lose all of the links between the tables - even if they show up in the Database Expert, they won't work (speaks the voice of experience!) Crystal 8.5 and Crystal 2008 will hapily live together on the same computer, so what I've done in this situation is open the old version of the report in Crystal 8.5, then create a new report in the newer version of Crystal using the same tables. You should then be able to copy and paste the objects from the old report into the new one. The advantage of this is that you don't have to retype any of your formulas and you don't have to redo any of the formatting.
-Dell