first off, check if xawtv is installed, if you are using a new distro, it should be there, otherwise install it off the cd or http://bytesex.org/xawtv/
to get the bttv driver to work, you need to change the options to suit your tuner card. there are two ways to do this. Either in the modules.conf file so it does it everyime you boot up, or you can do it using the modular options before you want to watch tv, personally, change the modules.conf file.
you need to add an option line under the bttv line, like this:
options bttv card=* tuner=*
you must put the card number in at *, i think a list of cards can be found here
there might even be an example modules.conf file there. (man it sux posting from work were we are forced to work on M$ boxes)
hope you come right