I'm not sure what Keith used but when I first started out I used this free software - Likno - Fairly easy to use with limited styles in the free version but only good for making buttons!
This is another free progam which is a very much more powerful and works really well - GIMP - a real Paintshop/Photoshop-like free program where you can design buttons and design or import & edit logos too.
There is also Paintshop Pro & Photoshop - both you need to pay for and very good (although you may be able to find a free trial of each online). I use CorelDraw/CorelPaint.
It all depends on how good you are at using drawing programs and what type of buttons you are planning! You are quite limited by what size buttons the Beo software let you use.
UK freeview logos are available on the "freeview website" and there are loads of sites with the worldwide, terrestrial & sky logos such as here
I would be more than happy to help design some buttons if you need a hand.
Stoobie