Viral videos can make you become known.  It could drive people to your site.  If you plan it right, you could get a sizable number of email addresses and potential contacts (via a share this video with a friend template)

However, you really can't plan on creating a viral video. 

But you can hope your video could become one.  It should be unique, or funny, or newsworthy.  If these three adjectives are what would describe your video, then you're good to go! 

Upload it to YouTube and similar video hosting sites, write up a good introduction of what your video is, it could be the topic, a synopsis or the tags you use.  Make sure that people find it.  Make it easy for others to share your videos too!

You could upload it to your own domain. With a good domain name, your video could be found by a lot of people.  Something like ParisHiltonTrips.Com if you have a video of Paris Hilton take a fall somewhere.

REMEMBER: Viral videos could get you on the map, make your product or service be known... like the Geiko ads, even a caveman could do it.  But don't expect revenue coming in.  It's very hard to convert viral video watchers!

However, if you're running like say, a Work-at-home mom site, and you could show them how to make their kids behave while they're working, do a demo on video, then post it up your site.  Moms would soon be emailing their fellow work-at-home moms to view your video.