^Or just have a few second re-cap at the start of the film.
"A young Bruce Wayne witnessed a common criminal murder his parents. Vowing to protect Gotham City from injustice he became The Batman".
Or a Seinfeld-esque:
"Bruce Wayne went to the opera with his parents, yada-yada-yada he dresses up like a bat and fights the criminally insane."
I still think all future origins should be handled the same way Spider-man 2 recapped the events of the first film. Have a brief montage of the key moments of the origin as the opening credits roll- Parents shot, Bats, putting on the bat costume - then dive straight into the actual plot of the film.
I'm becoming more fond of my yada-yada-yada idea
But yeah Spider-Man 2 did it well, I also like the route Watchmen and Wolverine went with the mini-movies in the credits.