The former is easily converted to PAL - resize to 720x576, encode at 25fps and speed up the audio by 25/23.976 = 1.0427. AviSynth is ideal for this kind of processing, but if you're not inclined to make friends with it at this stage then VirtualDubMod or VirtualDub-MPEG2 should be able to do the same thing.
Converting interlaced 29.97fps NTSC into 25fps PAL is a more complex subject - there are several different approaches, quality varies.