I have an 85' f150 with a straight six in it, but I sent my brother out to put a new battery in it and somehow he hooked it up backwards. I don't even know where to start on this so any help is appreciated.

 

What are the symptoms? Was there smoke or burning smell? Are all the fuses OK?

 

I wish I was there when it happened, but unfortunatley I wasn't. The fuses are all good, and I replaced the fusable link. I was able to jump it across the selenoid and get it to turn over, but I still don't have any juice to the key switch?

 

Which link did you replace? There are several.

Here is diagrams of the Power Distribution System.
Note the pages are from an '86 manual.

Batt. Fuse Links, Alt/Reg and Light Switch etc:
http://i608.photobucket.com/albums/t...0/F150PWR1.jpg

Ignition Switch and Fuse block etc:
http://i608.photobucket.com/albums/t...0/F150PWR2.jpg

Location Chart:
http://i608.photobucket.com/albums/t...0/F150PWR3.jpg

Test fuse link M. That is what powers the ignition circuit.
If that is the Link you already replaced then check it again.
If bad again then suspect the Alternator/Regulator (shorted diodes). If Alt. and/or Reg. has a short then the link could blow again.
To test for shorted Alt/Reg - Using a good charged battery:
1. Disconnect the alternator/regulator.
2. If needed replace the fuse link and see if the engine starts and runs with battery alone. Or have the alternator bench tested at an Autoparts store.