File > Export > Quicktime Movie
Name and choose location.
Settings: Current Settings
Include: Audio and Video (unless of course your video in silent, then you can just include video)
Make movie self contained is checked.
You may also like to export a version specifically for the web (eg. your blog or vimeo), so it will need to be compressed into a smaller file.
File > Export > Using Quicktime Conversion
Name and choose location
Format: Click on Options.
Video Settings > Compression type > H.264
Frame rate: Current
Compressor Quality > Best
Uncheck prepare for internet streaming.