The Apple (UK and Ireland) homepage is showing that the iTunes store is now open. I haven’t actually bought any tracks yet though.
Pricing is reasonable, 79p a track is below what the 86p a track that some people were thinking. That still makes it about 40% more than the US iTunes store. (79p is worth about $1.43 at today’s exchange rate). However it isn’t too bad and is somewhat better than the 99p a track some people were suggesting.
(Currency conversion at xe.com)