Apache on local machine but opened up to a specific 3rd party

Hi group,

I need some advice...

I'd like to set up Apache on my home PC so that I can run Subversion
and a Wiki. I'd also like to open up both of these things to a
specific 3rd party so that if we want we can do a bit of collaborative
development. My set up at home is not exactly ideal for this (W2K
Pro/ADSL/Dynamic IP/Draytek Vigor2600G/McAfee anti virus/Sygate Pro)
but I reckon it will be doable (correct me if I'm wrong).

Since my router supports VPN I'd like to set one up. If I understand
it correctly, that will give the person connecting access to my hard
drive. What I don't quite understand is where Apache fits in. Is it
possible for the person accessing the VPN to access my private copy of
Apache (ie its always hidden from the oustide world). Do I even need a
VPN for this? Obviously the connection needs to be secure.

As you can see I'm struggling a little. Any tips or nudges in the
right direction as to how to set up my desired system would be greatly
appreciated. I wasn't even sure what to type in the first installation
dialog when installing Apache. Do I want the port 80 option or the
port 8080 option? What do I type for the host and server?

James