One way. When you check out the code, look at the last line of svn output:
$ svn up
...stuff...
Updated to revision 66593.
A more direct way:
$ svn info
Path: .
URL: https://svn.example.com/svn/myproject/trunk
Repository Root: https://svn.example.com/svn/
Repository UUID: d2a7a951-c712-0410-832a-9abccabd3052
Revision: 66593
Node Kind: directory
Schedule: normal
Last Changed Author: bnguyen
Last Changed Rev: 66591
Last Changed Date: 2008-09-11 18:25:27 +1000 (Thu, 11 Sep 2008)