As the Mozilla project is planning to dual-licence all its code I believe it would be great for k-meleon to use the same licence as the Mozilla codebase which is going to be a dual MPL/GPL licence, this would make your code useful to a greater number of people and would make it easier for any modifications you make to be incorporated into the Mozilla codebase. As someone who uses Mozilla (the full thing) I'm hoping that projects such a kmeleon and galeon will help find bugs in gecko and make it the most stable and standards compliant rendering engine around.

Useful links
Gecko Embedding details:
http://www.mozilla.org/projects/embedding/

Mozilla relicence FAQ:
http://www.mozilla.org/MPL/mozilla-relicense-faq.html

This probably does not need to be addresses until Mozilla is mostly finished with it's relicensing campaign.