"Time travel is a bitch" - Sawyer from "Lost"
I was just browsing this site Entertonement.com which has a wealth of clips from everything and anything imaginable including Time Travel related quotes like the one from Sawyer above.
There's also the sound from Lost when they are travelling through time.
You can also find audio clips from Terminator, Back to the Future, and Dr. Who television series. Surprisingly there are very few clips from movies like Bill and Ted's Excellent Adventure or say Donnie Darko.
Let me know if you know of any other great sites for sound clips (especially time travel / sci-fi related ones).
I'll leave you with this last one with wise words from Doc Brown.