When I first went back to work, I sent this booklet around to my boss and colleagues so they could have a general understanding of brain injury, and then I talked to them about specific issues I knew I was having:
http://mayoresearch.mayo.edu/mayo/re...-employers.cfm
I pre-arranged a place I could go to lie down if I got a headache or got overwhelmed. I also made sure I had an ice pack and headache medication ready. We talked about fatigue and the idea that I might need to take more frequent breaks or go home early.
If you are using any modifications at home for your computer, be sure to have those set up. Might not hurt to have an ergonomic review of your workstation?
It also doesn't hurt to have your doctor document your issues and what types of accommodations you might need in case somebody wants to get pushy about it.
Good luck!