external box
Well, since you have a Powerbook, you can't use a PCI card.
You need a MiniDV camera or an external box.
There are 2 mains types of coverter boxes:
1. Convert to DV
2. Convert to mpeg1, mpeg2, mpeg4
Formac and others convert to DV
ElGato, Plextor and ATI covert to mpeg 1, mpeg2, (sometimes mpeg4)
I haven't experimented with the new versions of the iApps, but the old ones didn't play nice with mpeg video. There were conversion steps that needed to be taken. The iApps used to be specialized for DV and jpegs. But now are things are changing since iMovie now accepts mpeg4 and HDV(consumer high definition video, which is based on mpeg2.) Also iPhoto 5 now accepts mpeg4.
It also depends on your analog video format. DV has much less compression than the mpeg formats. If you are going to do alot of editing then I would use DV. If you just want to convert a vhs tape (or TV) to DVD, I would get a mpeg converter. All the mpeg converters mentioned come with EyeTV which lets you edit mpeg video, and it can also be used like a Tivo.
Good Luck