How to make installed port version the default one?

[antonio.grilo at inov.pt]

Dear all,

I'm new to the Mac world and so this is probably the most stupid 
question that someone has posted here.
I have installed Xcode3, which comes with gcc42, but I needed gcc43 or 
higher and so I have installed gcc45 using MacPorts. The port is 
reported as installed, but whenever I run gcc, the release gcc42 is 
always invoked, as if gcc45 was not present in the system. So I can I 
make gcc45 the default version? Thank you for your patience.

Kind regards,
António Grilo