JOE,

The datasheet is your best friend in this case -

If you are using TMR0, you can poll like this:

Code:
loop:
if INTCON.2 = 0 then loop
'deal with overflow here
I have a clock example here that also shows polling of TMR0 for timing issues.
http://www.picbasic.co.uk/forum/showthread.php?t=2129

Also see Melanie's Olymic Timer here
http://www.picbasic.co.uk/forum/showthread.php?t=632

and Darrel's timer here
http://www.picbasic.co.uk/forum/showthread.php?t=190

for ideas.