yes correct fallback is important if its a responsive design you are building, less so if you are providing just a pure mobile option. encoding .com is also good as alterrnative to zencoder. I like this one as well to deliver to iphone and android
http://chall32.blogspot.co.uk/2011/0...or-iphone.html
also a good sniffer, iphoners have more money than android owners , cos they have to pay stiff monthlies to own it. dont forget the tel: and sms: html tags as well to launch their phone or text services rather than send them to a stupid credit card payment page.