My Macbook Pro has been doing the same thing ever since I upgraded to 10.5. Airport never stays connected and drops often.
When I called about it, Apple Support was very dismissive. 😡 After 2 hours and three levels, they blamed it on my router and claimed to never have heard about this problem before, even though I directed them to threads about this problem on their own website. Tomorrow, I am taking my laptop into the Genius Bar to see if they can help me there.
Has anyone else called support about this?