Mobile best-practice for Rails

I am looking for info on methods for making a Rails site more handheld device (pda,
phones) -friendly. So far I have found some discussions on this list that led me
to the following links:

I have also done some reading on WAP and WML, but not sure if I want to make
a separate WAP site.

I want to provide essentially the same content and basic functionality to mobile users.
This just means degrading CSS and AJAX.

One approach I have tried is to add :mobile => true to every generated link and use a
before_filter to check it. It had been mentioned elsewhere and is not difficult to auto-rewrite

A slight variation is to check the sub-domain instead (e.g. match on mobile*). This
is what I ended up using. I think it works well for pda and phones that support HTML
in addition to WML. That still leavesWAP users out in the cold.

I would be interested in hearing your opinions on the subject. Perhaps some of you
could point your PDA/phone to my mobile site and let me know if there are
any issues. I have tested with Opera 8 and Opera Mini 2.0.

Thanks for listening...