DV/DVCPRO is NTSC DV... it's shot by NTSC DV cameras... This is a very common editing format used for DV cameras.
The other two are delivery formats. H.264 can be used for the web movies and even for blu-ray disks... it's a scalable thing, and is a very advanced and very good codec to just use for watching the video but it's not editable easily at all.
The H.263 codec I'm not sure of what it would be used for, but figure it too comes from the MPEG family so wouldn't be editable, just viewable... what you'd use it for? I've no real idea, but would love for somebody to chime in with it's use.
Jerry