First off, I am not blaming anyone for the fact that I went through this.
I spent the last hour trying to get IC2 to work with Forge. I even got it down to where it was just IC2 and Forge. I added the API file just in case (despite all literature saying that I didn't need it). It just wouldn't work. I was using IC2 1.117.921 with Forge 9.10.0.804. I was sure I was using the right versions. Here's what I got the version information apropriate for the MC version:
http://www.9minecraft.net/industrial-craft-2-mod/
It wasn't until I noticed the area above the topic page had written v2 for 1.6.2 that I realized the version I had was for v1. However, even then, I had to figure out which version of Forge the IC2 v2 would like. I finally managed to figure out what version liked what. However, it would have been easier if I knew:
1) What the green lettering said (it's rather small)
2) IC2, with each new version, gets finicky about what Forge version it uses.