If you need to know whether your solaris machine is running 32 bit Solaris, or 64 bit Solaris, then type use the isainfo command:

Which mode your machine is running in:

CODE

bash-2.05$ isainfo -b 32 bash-2.05$

Which modes are you capable of running:

CODE

bash-2.05$ isainfo -v 32-bit sparc applications bash-2.05$

Here's a link from the sun site that describes how to boot in 32 and 64-bit modes (other good info):

http://soldc.sun.com/articles/64_bit_booting.html#Q6