Is it better to have srm as another vm (2003 std 32bit) or install it on the virtual center vm?
The answer for that really depends upon 1) the size of the environment 2) resources available for the vCenter server.
I don't believe I've ever seen a real recommendation from VMware, I generally start looking at a separate SRM server with 150 or more virtual machine OR the chance of growth in the foreseeable future. It can't hurt to just install as a separate server, especially if vCenter is a 32-bit server.
Tim Oudin
I would always recommend a separate windows instance for SRM...
As for 64/32-bit. I'm making the move over to W2K8-64-bit in all my VMware infrastructure where I can... I think we will be facing a 64-bit on version of vCenter in future - it kinda leaked out the rel notes for the last release of vCenter 4.0 U1
Regards
Mike Laverick
RTFM Education
Author of the SRM Book:http://www.rtfm-ed.co.uk/2010/03/22/new-administrating-vmware-site-recovery-manager-4-0/
Free PDF or at-cost Hard Copy