Higher Register Help!

Hey there,
So now i think I can sing to a reasonable level, I'm trying to learn to improve my higher registers. I can hit the high notes, but they tend to sound so weak,nasally and well... womanly :oops:. But I had something of a revelation today, I noticed that as I was going into my head voice, my soft palate was raising very high, so high so that it actually was allowing no air at all to pass through my nose. Hence making the voice sound a bit stuffy. So has any one else had this problem? And does anyone have any tips of how to work on it?

Thanks :)
Nath