I need something that will take images in BMP, GIF, PNG, JPG, and covert them into a format used as folder and file icons. I've looked a lot, but haven't found anything, anyone know of one?
You really weren't able to find one? There are billions of the darn things. Admittedly the good stuff is buried under layers of advertising, but still...

Anyway, here's one I found the last time I went looking: GenIconXP.
I was also looking for that sort of thing the other day. A really good one is Axialis IconWorkshop. Not only is is super-great at creating icons, but you can convert any image to a .ico, and vice-versa. It even gives you tons of options for conversion. It's really great.
The BYOND program icons were converted to .ico using ArtIcons. It worked so well that I went ahead and bought it.
In response to Crispy
Well, I did find one or two, but they left watermarks and didn't have transparent backgrounds. =\