Is Worms 2: Armageddon available on PC?

Yes, of course. It's called "Worms: Reloaded" and is available on Steam and retail. It includes everything from W2A + Battle Pack and some PC exclusive content such as Community Missions, extra forts/hats/etc.

There you go:
http://store.steampowered.com/app/22600/

Ah right, that would explain why I couldn't find "Worms 2: Armageddon" anywhere for PC lol.

Cheers guys, appreciate it.