But can anyone explain why it wouldn't be a good idea to set about getting inspectors in to Iraq at this point? Why hang about until some new resolution can get hammered out or not?

I was glad to see that's the position Ireland is supporting, as one of the junior members of the Security Council. (So the UK is supporting the USA position, and Ireland isn't - that must confuse a few people.)

There's no reason why the presence of inspection teams under the existing procedures should get in the way of the US ("and the UK") trying to persuade the rest of the Security Council to agree on a new resolution. And if Bush can't get his resolution and decides to go to war anyway, he can still go ahead. He's just got a resolution through Congress that allows him to do just about anything he wants to do.