Yes. Windows XP and Server 2003 Standard allow one local login plus two Terminal Server (remote desktop) sessions. Windows Server 2003 Enterprise and Datacenter Editions allow more (but nobody ever bought those flavors because Standard was so much cheaper.) I'm not familiar with Windows 2008 Server but the policies are probably similar.
The limit of two remote sessions in the regular editions is arbitrary, but was chosen mostly for RAM constraints; the windowing environment for each user plus the tasks they're likely to run will consume a few hundred MB of RAM or more. The advanced editions support RAM beyond the 4 GB 32-bit limit.