Just installed the 7000a-AlCu on my AXP 1800+ (switched from a TT Volcano 6cu).
The Zalman is much, much more quiet, and seems to cool extremely well. My temps used to be around 40C (with a 30C case) and now they are closer to 35C with a 30C case.
If you go to the Zalman website you can look @ their Motherboard compatibility specs to see how it will work. You may also need to check your case for clearance as well (mine just bare cleared the PSU).
http://www.zalmanusa.com/usa/product/view.asp?idx=54&code=
That should get you to the right page.
I really like the Zalman, but I was switching from something very loud. Therefore I was easily impressed. What I really like about the Zalman is that I will be able to use it when I build up an A64 System in December.
Also, I bought mine from a store near me called Central Computer:
http://www.centralcomputer.com/emerchant/itemdetail.asp?item=CPUZZZCFSHKR
I always go to their actual store to buy, so I don't know what their online experience is like. However, they are pretty cool in person, so maybe that's a good sign.
-D'oh!