How do I create a comma delimited string from an ArrayList?

I'm storing an ArrayList of Ids in a processing script that I want to spit out as a comma delimited list for output to the debug log. Is there a way I can get this easily without looping through things?

EDIT: Thanks to Joel for pointing out the List(Of T) that is available in .net 2.0 and above. That makes things TONS easier if you have it available.