I too have a AMD X2 6000 I replaced the supplied heatsink & fitted an Artic freezer 64 pro air cooler to it & it works fine, temps are
Idle Core 1 - 33c
idle Core 2 - 33c
Load Core 1 55c
Load Core 2 54c
The cooler is available at Ebuyer, Teheads & Scan computers for about £14 like everything you can get better depending on what you want to spend, but for the money it is a good quiet air cooler. Also once the load on the CPU is eased it brings the temps back down very quickly which not all coolers do particularly well
Try this Vigor Monsoon II Thermal Electric cooler. I have it on my Opteron 185 @3.0Ghz with a 250mhz FSB at 1.4vcore.
If I turn on cool and quiet it idles at 22c. Without CnC overclocked it idles at 38c and has never gone over 47c under extreme load.
Sorry that Newegg is currently sold out. The damn thing seems to work perfectly and this is surely why its sold out. One important thing you need to know is that you have to take your motherboard out to mount the backplate on the back of the motherboard. Kinda time consuming but well worth it. Its also not as noisy as some reviews may say but you will notice it if you're coming from a near silent setup.
For most stuff, Scan usually works out at about a 5er cheaper... but their customer service, in particular their RMA procedure has been shite in my experience. Good for the mainstream enthusiast stuff (I'd liken it to the UK Newegg)but its OCUK for special, Quietpc for quiet...