I don't remember the website but I did a google search on "dog car seat". They are a little bit pricey but well worth it. We had to take a long road trip (11 hours) and I really wanted to take the babies. They both sat in their own seat the whole time, except potty brakes of course. I was shocked how good they were. I use them all the time.
Try this site:
http://www.healdsburgdoghouse.com/snlobo.html
If I can think of the site I got mine from I'll post it.
Jennifer