First of all, there really is no glamour to being a Cherub. We are the lowly folk here at Heaven, who dont have ftp access and cannt do much. Me for example...the only part of HGS I can do anything with are these forums...I cant do anything related to any other web pages.
I dont think AOKH is in need of cherubs now, but when they are and ask for help or something just email them saying you want to be a Cherub. Dont email omnivac asking to be a Cherub unless he asks for help.
If you are really good with web design you _might_ be able to skip Cherubness and go straight to being an Angel. If you apply to be an Angel, because of your web design/graphic skills, I cannot tell you what part of HGS you will be working with. They might need you somewhere that isnt AOKH, if so would you still be willing to accept the position? If not, then you might not have a place here at heaven currently.
When they want new Cherubs and Angels, they usually post it in the news.