Without knowing a lot about what you actually want to do it's hard to give an exact answer. But basically if it's it only 2 selections, like what is typically done with a Start & End date search, one way is to make 2 global fields, make them dropdowns tied to your parameters (hard coded or based on a field). Your 'Go' button would grab the 2 fields and perform a find. Either you would grab the values and concatenate together, or you will need to:
Enter Find Mode
Set Field (first parameter)
Set Field (second parameter)
Extend Found Set or Constrain Found Set, depending on what result you desire.
If you provide more detail, you will get a more detailed response
This has pretty much nailed it, thanks.
As I said, I was (for some reason on this one) stumped, but can create a pretty cool routine now.
Thanks for your help