If you do want to play with it, I would suggest this:

Get two networked boxs that are not anywhere near an Internet connection, install the server on one and the client on the other - now play around with the different settings and methods of installation - and learn to your hearts content.

You could even introduce different AV's and firewalls to see how they handle it and to try and find away around them if you really wish to.

Some of the settings wont work such as notification via E-mail/ICQ etc as obviously there is no internet connection but the vast majority of its functionality will still be there.

But when you have finished and go to put the boxs back online - I would advise a bloody good format first!!

Enjoy!

/Be aware though that most versions have another backdoor coded in to them - to install it on your machine with out you noticing. Couple this with the fact you will need to disable your Av and firewall - or at least configure them to ignore sub7 - and you could have a dangerous backdoor installed! Sub7 may be old but it can still do a lot of damage!
Be very selective where you download it from!