Split & Concat 2.5 appears to work fine on my intel mac running leopard, I tested it by splitting a 1.6 GB toast file into 100 MB parts. I did notice that when concatenating back, the custom icon was lost but otherwise the file was ok.

This program is so intuitive to use, I didn't bother reading any of the documentation. One tip I will pass along is to put the file you will be splitting in a folder by itself, likewise when concatenating, put all the parts in a folder together.

This is a very useful utility.