My Quad Core Q6600 machine used to average approx an hour in DVD Flick, the latest version of Flick (1.3.0.6) seems quicker than an hour though (as daft as it sounds) i hadn't yet taken the time out to check the runtime, will have to check that next time i'm home.
I'd hazard a guess that a couple hours is correct for a P4 CPU such as yours. I've recently started using of of my Dual Core machines (E6400 CPU, 2.13GHz) for dvd/avi work, but haven't yet used it for DVD Flick so can't give a runtime for Flick.
On my PD dual core, I find when I use dvd flick, it sometimes can take about as long as the movie is to convert. A 90 minute movie may take anywhere from 85-95 minutes. I usually have it running at "low priority", and if I have additional steps to use (subtitles), then it usually takes a bit longer.
2 hours to convert AND burn actually sounds pretty good!!!
I have an older desktop (built around 2000 give or take a year) that has a Pentium 4 (I think its a 3.2Ghz, but not home now, so can't check) and only 1GB ram.. Gave up on trying to convert and burn anything on it.. Took at least "8" hours to just convert a 2 hour movie (approx 700MB .avi), burning took at least another hour or so.. (antique NEC burner.. top speed not even 4X).
Needless to say, don't use the desktop for burning anymore.. Laptop much much faster.