Dont feel shy about posting a topic to ask if your kitty is a tortie or not. xP Some of us here I am fairly sure will give their opinion on if we believe it is a tortie-breed or not. Also a good place to go read to see if your kitty is a tortie is wikipedia. Here they have a good number of pictures of regular calico cats, and torties so that you may see the difference. xP
As you can see there are a few torties that have a little bit of white on them. Comparing the pictures with the regular calicos shown you can see the difference in the amount of white on the kitty. There are even some pictures of the mix-type torite/calicos called "Calibys".
So if you have any questions or you wish to know if you should post your kitty photos here, dont be afraid to ask!