Infrared filters?

I'm too broke to be able to afford to send my spare digital camera in for modification to make it a dedicated infrared camera. I've seen filters being sold that are supposed to give somewhat of the same results. Anyone use these? How do you focus when you've got a huge dark filter on your lens?

i'm confused why anybody wants to convert an slr to IR anyway. (for that reason) I don't recommend doing it yourself but I converted a coolpix 950 to IR.. took it apart and replaced the IR blocking filter with a plain piece of glass and mostly put it back together (hence the don't recommend part) then screwed an IR filter on the lens (have a 37mm for video just bought an adapter)

I look at the little screen and I see IR images... [shrug]

you HAVE to remove the IR blocking filter or expect exposure times in minutes.

without it, everything has a red tint...

you could convert your coolpix to IR Pass for not a lot. If you put an IR block filter on its just like before, if you put an IR pass filter on it you have an IR camera that will expose in bright sun pretty fast.