One light year is the equivalent of about 5.9 TRILLION miles.  And the observable universe is about 14 BILLION light years across, which is way too big to even imagine.  But there's a cool website that can give you some idea of how small we all are.
It's called ScaleOfTheUniverse.com, and by using a slider at the bottom of a flash video, it lets you zoom in and out, showing the size of an atom compared to the Earth, compared to the whole universe.  Plus, it shows everything in between.

http://www.scaleoftheuniverse.com/