GriP (Growl for iPhone) is in beta now.

Let me cut it short: you can download GriP 0.1-11b (beta) from http://code.google.com/p/networkpx/downloads/detail?name=hk.kennytm.grip-0.1-11b.deb now. The documentation is also available in http://code.google.com/p/networkpx/wiki/GriP, which contains most thing you are interested. It should run flawlessly on a jailbroken 3.x device too, but I haven't tested (I don't have a 3.x device right now).

self notes...

[UIFont smallSystemFontSize] == 12
[UIFont systemFontSize] == 14
[UIFont labelFontSize] == 17
[UIFont buttonFontSize] == 18

Default font size of Rounded Rect button == 15
Default font size of UITextField == 12