1) A mill can make threads. Tapping obviously, and then there is threamilling if the machine has 3 axis simultaneous control.
2) I've recommeded the Syil X4 or larger machines to a couple of people recently based on friend's experiences. They are fairly good for the money, and from what friends have said they apparently have decent support. I would get as stiff and tight a machine as your budget will allow if you want to cut titanium, it's the devil of a material. I make a few aircraft parts and some MotoGP parts in titanium, using full size industrial machines and can have problems from time to time - I don't think I would relish the headaches on a home-size machine (atleast what normally qualifies for home-size).
I've got a Sherline that I would be interested in passing on, but only to someone in the Texas area. I had tried to sell it before and getting pictures and videos of the machine to someone drove me to distraction. It would not be appropriate for any titanium work though, that's for sure.
3) The Syil X4 uses Mach3 for the CNC control program, and there is a very cheap program from the same group called LazyCAM that will do a few basic things for you - it uses dxf files and such for toolpath (
http://www.machsupport.com/downloads.php) . Seeing as you're using a solid CAD program, I would suggest you go a bit more sophisticated though, maybe Rhino or Alibre for your initial CAM solution. I use MasterCAM X4 and EdgeCAM and wouldn't even think about going to anything less fully featured. You'll probably get set up with a particular brand of software in the course you're gonna take, so you may just want to go with it (CAM programming is almost always a course within machining curriculum.
Rgds,
John B