If you don't know the answer to your question, I would consider you an idiot for considering doing this yourself. Of course you could of meant that as, you're planning to get your eyebrow pierced, and in which case its all up to personal opinion. The majority of people will go for a barbell, straight or curved, while others go for a ring or custom jewellery. Materials should be an implant grade metal such as 316LVM steel or a bio-compatible plastic compound such as PTFE. Regular sizing for an eyebrow are generally (in my country anyway) 16ga (1.29mm) or 14ga (1.63mm), although I've seen other places do quite a lot of 12ga eyebrows. This is of course just a generalisation and it's completely up to you. Length/diameter of jewellery will vary dependant on your specific anatomy.
ya mine's done, and the curved barbell looks pretty wicked on me. it's all bout how your face is set up dude. but if you are going to pierce it yourself, you might want to think again.
Definatly go with Stainless steel barbell. Cuz i got mine done and i took the barbell out and put a hooop in it and it go infected really bad. and always clean it with antibacterial soap. Dont get makeup or anything like that around it cuz it will set up infection.