The current versions of Uleads VideoStudio and DVD MovieFactory both support 64 bit XP.
VideoStudio 10 Plus requirements page....
DVD MovieFactory 6 Plus requirements page....
I'd recommend the Plus version of VideoStudio because it features a 7 video track timeline, which allows for numerous video overlays while the "plain" version only allows 1 overlay and a title. It also offers 5.1 Dolby audio.
DVD MovieFactory 6 Plus offers HD DVD and Blu-Ray export support, AVCHD and DivX imports, basic edits. It too offers 5.1 Dolby over its "plain" version.
Both plain versions can export stereo Dolby.
All versions support LPCM and MPEG Layer 2 audio for DVD's.
Hope this helps.