To look at an older strip add the date:
www.ucomics.com/tankmcnamara/2005/01/29/ for last Saturday's, for example.
I used to check Tank and other comics at the Washington Post website (at least the ComPost was good for something) until they started requiring registration.
use www.bugmenot.com for a free log in code if you want to bypass the registration process. Works great and you can remain anonymous.