Don't try to run before you can walk, I personally think you are much better of getting to grips with Photoshop before making the jump to buying a Wacom Tablet. You can always purchase the Tablet when you feel more comfortable with Photoshop at a later stage.
Photoshop requires a lot of patience and practice as does learning to use a Wacom Tablet.
Totally agree - although in the long term many people find that a graphics tablet is a far superior input device when using Photoshop you might be surprised at how many people just don't take to it. Completely agree with Ged that it is a very specific skill to learn and your time at this stage is almost certainly better spent getting to grips with the basics.
There can be a tendency to think that the more gear you have the better you will be - this is only true if you get to grips with the basics. To go back to my driving analogy, my brother has a Ferrari sitting in the driveway, and that is where it will stay until he has had a few driving lessons! (BTW - my brother wishes the previous statement was true
).
Your suggested starter project sounds excellent - follow Geds links for Masking tutorials. Probably (in my opinion) the most important concepts to get you head around are Layers, Masks and blending modes.
Best of luck - and keep asking!
Cheers
John