I have tested and run TP 3.1 and 4.0 and even to an extent 4.6 on both windows xp Pro 64bit and Windows Server 2003 X64.
Runs like a top.

Two questions,
One, is there a migration tool to move from TP 3.1 to 4.6?
I have been having problems with the virtual hosts and the way the ssl is configured, keeps going to some default page.

two, is there in the works a plan to port apache to the 64Bit Operating systems?

I would really like to get apache 2 running on the multi core multi processor server I have set up so that I can check the differences from apache 1.3

Any suggestions?

Yet, there are no migration tools for TP. Basicly, all the configuration is generated from the setup.ini file. You can update it and re-generate using setup.php.
Regarding ssl and vhosts, what are the problems you have?

As of 64bit, no we have no such plans, it all runs on 64bit OSes in 32 bit mode. Probably, we'll think of it in the next year