And since they use a standard (RFC6238), there are third-party application that works with it too. I use a J2ME app on my Symbian phone.

What J2ME app are you using? I ended up porting (really just copying one Java class) part of Google Authenticator to J2ME. It works, but isn't great. What're you using?

(Sorry for the late reply)

I use an app from DS3: http://ds3global.com/index.php/en/news-a-events/news/97-secu...,

It's extremely simple, it just generates OTPs, nothing more.