Thank you guys for the input.
The reason I ask this is because I am about to build my first computer. I am able to just barely pull this off on my budget and buying a computer case would break that budget. So I am going to use an old computer case for my new computer-innards.
On my old PC case, the PSU lays side ways. The old PSU (Which I am going to be replacing) blew air directly against the CPU heatsink and its fan. The old PC case I am talking about is for a PentiumII CPU, the computer is made by Packard Bell.
The new 12V ATX PSU that I am getting will be drawing air from within the case and blowing it out of the case.
The PSU and CPU heatsink/fan will be about a half inch from each other (assuming everything fits together in this case).
So, I figured having the CPU fan blow air directly into the PSU fan intake, to be exhausted out of the case, would be the best scenario, I just didn't know if this was against the rules of cooling a CPU or not.
The real downside to this is that the PSU I am buying is cheap. And I know that the more heat these things are under the less watts they can properly deliver. In this scenario the PSU will have all the CPU heat blown directly into it.
In case it matters, the CPU I intend on buying is AMD Athlon 64 X2 5200
2.7GHz @ 65W
It's retail, and says it comes with a heatsink and fan. I assume it comes with some kind of thermal compound too.
The PSU is a HEC 585W ATX12V
HP Pavilion 7920
901MHz Intel processor, 256MB SDRAM,
30GB & 250GB IDE Hard Drives (NTFS)
Audio= Intel 82801AA AC\'97 Audio Controller
Video= Intel 82810 Graphics Controller
OS= WinXP Pro / SP3 (32 bit)