list of channels available

[Simon Kenyon <simon@xxxxxxxx>]

i'm trying to use the data with mythtv
three questions:

is there a channels.xml (or whatever) which contains the list of  
channels available?

is there any way to get more channels available? i live in ireland, so 
bbc1/2 (northern ireland), utv, rte1, n2, tv3 and tg4
are of importance to me. i also get sky digtal, so i would like to get 
some of those channels as well
sky cinema 2 and sky sports 2 comes to mind

where is the original data coming from?

thanks
--
simon