I assume you could use rEFIt and Boot Camp like you would with GNU/Linux or FreeBSD. Do a Google search if you are unfamiliar with the usual dual boot setup.
Macwhiz, I hope you don't mind me asking, but why you would run Solaris on a MacBook or MBP (in favor of Mac OS X, GNU/Linux, FreeBSD, etc.)? I think of Solaris as strictly a server OS and certainly not meant for laptops. Instinct tells me that trackpad support and power management will be big issues. The only possible reason I can see for dual booting Solaris is if you have a Solaris server and you need to test web applications on your MacBook. But even then, your web applications would probably be written in Java EE, in which case Sun Microsystems would tell you that they can be "run anywhere." If you intend to use Solaris on a laptop for your daily computing needs, I would open Google Earth and look for the nearest psychiatric practice. I prefer Ratpoison and other keyboard-controlled window managers to Mac OS X's Aqua GUI, but even Aqua beats Solaris's Java Desktop System. Please clear up my confusion.
P.S. Don't construe this post as an anti-Solaris campaign. I like it for servers, I just don't think it has any purpose on a laptop.