I have Yellowsdog Linux on my Playstation 3 and it is Dog Slow.
Can I install Haiku on my PS3?
The PS3 has 256 megabytes of memory so I guess it meets the minimum requirements.
If not, then can I dual boot it with my Vista on my main machine?
The PS3 has a very unique hardware and software architecture that mean it’s very unlikely Haiku will ever run on it.
As for dual-booting with Vista that is very much possible, there are some instructions available here that might help you get started: http://www.haiku-os.org/community/forum/installing_and_dual_booting_haiku_and_windows_xp (intended for Windows XP but should be useful for Vista as well).