Question : Problem: Iphone and Exchange

Corporate environment, want to push email onto the Iphone - retain user identities.

What options do I have.

Answer : Problem: Iphone and Exchange

The new 3G iPhone which is out on 11th July (in the US and UK at least) will do Exchange Direct Push e-mail with remote wipe capabilities thats your best bet.  If you have the old iPhone your best option at the moment is to configure IMAP4 connectivity on your Exchange box which the current iPhone supports.