I've experience with cluster software from SUN, HP, IBM and Veritas.

First thing you need to do is make a cost analysis. Clustering isn't something you implement on a rainy afternoon. You need hardware, software, and training. And clustering doesn't necessarely improve performance (in fact, performance isn't the usual reason for clustering - reliability is more important). For the problem you describe, I highly doubt clustering is the solution.

And if you think it is, don't go to Perlmonks for answers. Talk to a couple of vendors that provide solutions for your platform. Ask what they can do for you, and how much it'll cost.