Fuck Yeah, Guys in Tights is exactly what it says on the tin, with dancers, athletes, actors, drag queens, matadors and guys who are just plain stylin’ (and have great legs).
Fuck Yeah, Guys in Dresses (I don’t think it’s by the same people) is your #1 source for men who make wearing dresses the manliest thing you could ever man.
Men In Dresses interprets its brief widely, and is a great collection of pop culture cross dressing.
Also awesome is His Black Dress, “about men rocking skirts, dresses, & heels as everyday attire”. I’ve linked to his Blogspot because it’s completely dedicated to the blogger’s personal style and philosophy, but Michael also has a tumblr which is more personal.
I gotta go to bed now - if anyone can recommend a good site for men in “women’s” clothing (“I beg to differ. This is not a woman’s dress, this is a man’s dress.”), stick it in the ask box!