Thanks for the kind words guys, it's great to hear people are getting some use out of this!
I probably won't develop this for other phones, simply because the UI I used is iPhone specific, and would require basically a complete rewrite for other devices. You should check out gearchart.com from your phone and see the mobile redirection is working for you. He put together a mobile version as well, and it's more friendly across many different phone platforms.
I initially just wrote this for myself (since I use an iPhone), but noticed a lot of other guys use them as well, so figured I'd release it for others with that device. I never really wanted to go for the whole mobile segment, I think Harsh's gearchart.com does a fine job of that.
It is definitely possible to write native apps for many portable devices (phones included) so that you can do this offline. Eventually I'd like to get around to making a native version for the iPhone/iTouch, but I've been pretty busy with other projects, so a web version is the best I can do for now. I don't know about availability on other platforms. I thought, at least, there was some Palm thing floating around. Also, for the iPhone folks, check out Snowy's post earlier in this thread. The program he suggests is pretty cool!