The event is Wednesday, 8th April starting at 6ish. Beer of the Month is still listed as Fat Yak on the website but as it's April 1st you never know.
Thus far it looks to be shaping up as a good event with:
Jeremy Thake - SharePoint and TypeMock
Rhys Campbell - WinForms
Stephen Price - Silverlight
Tiang Cheng - ASP.NET with WatiN
I don't have a link for Tiang but he sent me this:
Don't forget to bring your Coding Ninja outfit (I refuse to call it a Gi) and be prepared to jump in at a moments notice. Also, just two last things. 1) If you are coming please register at http://perthaltnet0904.eventbrite.com/ 2) Tell your friends (or if you think TDD is stupid tell your enemies). That is all. See you there.