i've seen a few episodes, and i can see how the Sheldon character has some Asperger's traits. i liked both Penny and his role. something in the timbre of the others' voices annoys me, though.
side note:
the initial draft of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) is posted up for review and comments at
http://www.dsm5.org/Pages/Default.aspx until 4-20-10.
some folks were just talking about it on my hometown forum.