Well I don't need help, but I can help you..Hopefully..
Is your hair already the right color? I see the character in your signature there so I assume you wanna do that to your hair..This is a very common style right now so..
What I would do is first, make sure your hair is short enough. Just go to a hair salon and have them cut it to that style..Most professional shops (not mom and pop barbers) will know this style very well as it's popular..Do this at the very most a WEEK before con..Not like, right now..It will start to get too long by con..Then bleach it..I'd also do this the same day you cut it. Also that short time won't let it grow out enough to show roots, so that's another reason you wanna do it so close to con. If you already have blonde hair, then skip that last part lol..
Next is styling. Go buy 2 products. If you have a Sally's Beauty Supply near you, that's best. If not, look them up..The first is Beeswax. It's a palmade that is very VERY strong. It will make your hair look like that with almost no effort, while still not being rock hard or flaky..I use to use it ALL the time..
To help visualize..I did this with only 2 fingertips worth of the stuff and rubbed it in my hands:
http://i88.photobucket.com/albums/k188/RazorXCore_2006/mohawk.jpgThe second product is called Un-Do Goo.
http://www.malibuc.com/products/cn/2410/Malibu-C-Un-Do-Goo-Clarifying-ShampooIt's the only shampoo I've found that takes out beewax in one shower..lol
Be sure not to overdo the wax amount. Too much will make it hard to get out.
And in case you haven't heard about it, yes beeswax is MEANT for hair. It was originally for black people because they could make their hair stay better or something, but it works great for these things..Also, the good thing is the heat at this con still isnt enough to make it fall flat like gel ends up doing. Back in middle school I use to use it a LOT and I put my old ACTUAL mohawk up (not that pic, that was way later for fun) and not one single day did it ever fall flat.