My guess is, you're using S-Video?
Well, rest-assured, unless you're using DVI on an HDTV, your image will be *****.
I used a 53" television as my computer monitor for a year and a half. Of course, this was mostly for gaming - but I did manage to use AIM and mIRC on it (although, it was a major strain on my eyes).
Don't even bother with televisions unless you have a really nice TV and your computer supports DVI-out.. Invest in a CRT if you're on a budget, but still want another monitor.
I don't think the Mini can even support DVI-out. But, I admit, I'm too lazy to go look.
Either way, hooking your computer up to a television has always looked terrible (until DVI and HDTV came along) - especially for text. You'll notice that it's decent for gaming or movies though. It was designed for things like that - mirroring your slide-shows and all of that nonsense to 'show your happy family' - presenting to clients (using pie charts I guess?), etc.
Pretty lame if you ask me, but that's the way it goes.
If you want to view text on a bigger screen, it's going to have to be a computer monitor or a really hot TV. Sorry.