I created an animation in blender (26 hours of rendering on 3 computers) and audio tracks for it.

When I tried to build the dvd it came up with warnings that the animation was only 25 (pal) fps. Timing of the video and audio are all done at 25 fps (oopps).

How can I convert the video to ~30 fps without the video and audio being out of sync?

So you want to reencode this pal video into ntsc, right?

Assuming it's a simple mpeg2 track, and not something with multiple audio or subtitle tracks, then ffmpeg is probably the fastest and easiest way to convert the framerate.

..should convert it to 720x480 ntsc-compliant dvd video.

If your frame size is different from the standard and want to keep it, use the '-s' option to set the correct size (ex. '-s 640x480'). See the man page for more details, or to set other parameters manually (instead of using the automatic 'ntsc-dvd' settings).