Went to local Ace hardware store to get some brass rivets for a sheath I made(like the looks), anyway bought a bunch of them thinking that all you did was put them on a hard surface and peen the bottom to flatten out, well that didnt work so can anyone tell me if there is a special tool or a different way to do it. They had some split rivets but the heads on them were too big to look good on my small sheath....Thanks, Dean-- If you have a pic of the tool if there is one could you post a pic of it..??

You need a rivet gun. Simple tool.. Load the rivet, insert into hole and squeeze the handle a couple times till the pin snaps.

The end..

Yup, you'll need a rivet setter to make them look nice.  Look for a local Tandy leather store for all the tools you'll need.

 http://www.leatherfactory.com/products.asp?number=8105-00

Assuming you're talking about two piece leather rivets like these:
http://www.leatherfactory.com/products.asp?number=3635-00

If you mean the pulled rivets like you use for sheet metal, then you'll need the rivet gun.

Thanks, kinda thought might be what I needed.

Go to the leatherfactory web site shown above and you will find rivets and the tools for proper installation. I also use Chicago screws on some projects instead of rivets and they are also available from leatherfactory.

The tool required, Depends on the type of Rivit used....
   I use 3 differant kinds of rivits and use a differant tool for each one....
   As mentioned above, the leather Factory will help you....
   They usualy show the proper tool on the same page as the type of rivit ya want....

Guys thanks for all the help, went to the leather factory site and will be ordering the stuff needed.Dean