Cgminer works on several cards at once. Its a bit more difficult to set up at first, but otherwise its a good miner.

As to CUDA or not, I'm honestly not sure. I'm pretty CUDA isn't the way to go, as I think OpenCL is better at integer arithmetic. But, its not too hard to try out several miners and figure out on your own.

A SHA256 isn't hard to compute, its just that you have to do a ton of them to verify a block

Almost all miners work in Linux, with many specifically targeting Linux. Look at cgminer or Diablo miner. Diablo miner is pretty straightforward and easy to set up, so long as you have Java installed. Cgminer can be a bit more difficult to get set up, but it offers a lot more features.

Yea, always trust the forum posts from the author of the miner or the official releases on sites like Sourceforge or Github.

Hi! Software developer and miner here. I've been interested in bitcoins since they first came out a long time ago. I don't have many mining rigs, but I am always looking to expand.

I've got a somewhat older GPU lying around that I decided to set up for mining purposes, as where its located I pay an all-you-can-eat electricity plan. Its running Win7 x64, ati stream v2.2, and poclbm but I never see it use more than 1% utilization on the GPU and its only going at 990khash/s max.

The card is currently running default speeds, latest Catalyst drivers, and nothing but Aero using the GPU at the moment.

Any ideas why its not using the GPU more?

EDIT:
I found out that it was reading my CPU as device 0 and my GPU as device 1. The guide I followed told me to set the device to device 0.