I've asked this question myself, and seen lots of people do the same too...the answer is no. Neither version of SSRS is cluster aware. However, since SQL itself is cluster aware, you pretty much get what you need (as long as you are using a web/reporting farm) anyway. Basically, you install the reportserver database on a clustered instance of SQL, then point each of the nodes in your web/report farm to the clustered resource.

For more information, see the "Server Cluster" section of this SSRS deployment whitepaper:

http://www.microsoft.com/technet/prodtechnol/sql/2000/deploy/rsdepgd.mspx#EGAA