Well, I'm not certain what all has been officially announced, but here is some useful facts concerning Vista.
1. There was one of those dreaded changes that happened right before Vista RTMed where a part of our installer framework no longer worked. Unfortunately, it was the framework that 8.20 shipped out with - and affects 64-bit Vista. That is the problem you are running into. LabVIEW 8.2.1 is going to be available soon and fixes this problem...I can't give a date on 8.2.1 until it's official announced - but let's just say that 8.2.1 has been closely associated with Vista, and Vista itself is going to be widely available on Jan 30th. No - I'm not saying it's shipping Jan 30th, but it gives you a bracket.
2. 32 vs. 64-bit support: Kernel components (drivers) must be the same bitness as the OS - thus, we are porting most of the drivers (see the list here) to both versions of Vista. HOWEVER, all user mode components are staying 32-bit for now. Thus LabVIEW, CVI, etc. as well as the user-mode API components of DAQmx, VISA, etc. are going to run in 32-bit mode only.
3. WOW Support: When running on a 64-bit Vista, you can run 32-bit applications under WOW (Windows on Windows). Thus you can still use LabVIEW, DAQmx, etc. on 64-bit Vista. BTW - the performance for WOW is very, very good - this isn't an emulation layer but a feature of both the AMD and Intel processors.
4. I strongly recommend LabVIEW 8.2.1 for Vista development. The earlier versions to "mostly" work through the backwards compatibility layer, so you can definately install them and use them. We have found various issues that needed to be fixed (espeically on 64-bit Vista), but you can do quite a lot with LV 7 & 8 (only two I tried) on Vista. If you have built applications, do make sure you test them under Vista for their own support level - there are always gotchas on a new OS, no matter how much backward compat. work has been done.
Let me know if you have other questions.