the icons are in an iconpackager container. a windows program like candybar. you can rename the .ip file you download to .zip and it will decompress it to to the two files that make up the iconpackager file, but i can not figure out anything further than that.
if you have virtual pc installed maybe you can download iconpackager [
www.stardock.com ] (iirc) and see if the program can export icons. it will probably export them to .ico, and then try pixadex to convert them. or maybe even iconographer.
or email the creator and ask him if he will send you the .ico files.