The best image selection I’ve seen so far [at least as far as seeing all of the HIMYM cast is concerned] is in the IESB gallery. [For more Alyson photos, try here or here. She went with her husband, Alexis Denisof, better known to some HIMYM fans as Robin's former co-anchor Sandy Rivers.]
I actually stopped by Grauman’s Chinese Theatre to watch the arrivals last night – nothing terribly interesting, except that Jason Segel made his way halfway down the red carpet before running across Hollywood Boulevard to greet the fans gathered across the street and sign some autographs.