Hi,
installing a new cam isnt that hard IF you know EXACTLY what you are doing.
Here are a few pointers.
1. Make sure you get new lifters.!!!!!
2. The cam should be supplied with grease - make sure you cover the whole thing in the stuff!!!
3. You should also get some 'break in concentrate' with the cam (really thick oil) use it!!!
4. Make sure the engine is at TDC when you remove the old cam, and install the new cam.
5. In the 4.1L's its actually easier to remove the engine to install the cam.
Also - when breaking in the cam, you have to make sure that you keep the car above 1200 for at least 45 mins (or 1500 for 30 mins) vary the revs, to change the oil splatter pattern on the cam.
After you have run the cam in change the oil and oil filter!.
If you dont understand any part of this, or are unsure in any way - get a mechanic to install it.
(If you are in Sydney, I can recommend a guy who will install for a very reasonable price)