debian lenny & blitzmax

Debian lenny doesn't offer g++ 3.3 via synaptic anymore. So treat me like an idiot, and tell me how to get g++ 4.x to work with blitzmax.

Also... is there easy way to get debian-lenny-64bit to work&compile? And if it compiles, is result 32- or 64-bit?

Afaik, g++ 4.x is unstable with BMax and may or may not work. If it's not working then you should just manually download the deb packages for i386 listed as red on this page:
http://packages.debian.org/stable/devel/g++-3.3

Not sure about the 64-bit question.

you need 32 Bit compatibility.

There is no 64 Bit Support AFAIK.
How ever - Results are 32 Bit.

You may have to create a chroot environment to get 32bit support on a 64bit environment.