User agents for mobile site, domain changing

Question

I have a mobile site and I\'d like to redirect users to the domain.mobi or mobile.subdomain (we have both setup)

1. How do I determine a mobile browser
2. Is it b

Answer 1

1. How do I determine a mobile browser

Here's some javascript that will do the job: http://www.quirksmode.org/js/detect.html

2. Is it bad practice to have the mobile site on a different domain or subdomain?

It's good practice, and a popular convention is to use http://m.yoursite.com for mobile if your main url is http://yoursite.com

Noah