Well, it's almost self-explaining. Put the BMPs you have done together with a txt-file with the explanation into a zip archive. Also make a screenshot of your skin/plane, fill in the form and then you can upload it.
![Smiley :)](http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
If you are lucky and the skins passes the quality test, HTC might include it for online gaming. Otherwise it will be only available for offline play.
I hope that will solve your problems.
![Smiley :)](http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)