Most pills have a window of about an hour or two in which you are still ok. Note, this doesn't mean that you should vary it like that all the time, but it's not nearly as bad as having not taken it at all, or been seriously late. So taking it as close to your normal time as possible is always going to be best.
You're most likely still ok, even with that single two hour variation. However, if you're worried, call your doctor and ask them about it. Also you can use a backup method of protection for the rest of the cycle if you're worried that your protection might have been compromised. Better safe than sorry, right?
Scarleteen Advocate (and Labia Lady)
"The whole world is full of morons...they just congregate on the internet cause it's easy for them to push the buttons."