i'm no expert by any means but i have been tuning via a tweecer rt for a while.
i would highly reccomend purchasing BinaryEditor and EEC analyzer (BE and EA)
the programs are much more supported and user friendly than the caledit and calcon (never used them to tune but i can see a huge difference just by fiddling with the programs) plus the creator actually updates and keeps on top of BE and EA. where i hear caledit and calcon are buggy and arent updated hardly.
as far as tuning goes its hard to say how hard it will be for someone just depends on the extent of ones mechanical expierence and how well they can familiarize themselves with how the EEC really works. i myself had never tuned before. i tried to read up on it as much as i could but everything is really confusing until you actually sit down and TUNE the car, make changes, see how things work.
i found myself super confused, i then got my tweecer, and dove in, i was expecting it to be hard as crap at first. but really it isnt that bad.
for most applications its really a matter of getting your injector slopes and etc sorted out. and getting the MAF transfer to accurate represent what your meter is.
the main goal i set before myself is to have the engine actually get the AFR (via WBo2) that the engine is commanding. once your engine is accuratly getting the fuel the EEC is commanding. then its a matter of telling the EEC how much fuel you want dumped into the engine and how much spark. to maximize, economy, performance and etc.
tuning for a mild combo with stock injectors would be super easy (if it even needed tuning at all)
my car is supercharged and a blown car needs a few more tweaks than a N/A car. but with my basic knowledge, i have managed to get my car running very well in a few months time. car starts, idles great and WOT is great also. the difference b/w the car untuned and tuned is HUGE, still have some small things to work out, slight lean tip ins, cold start warm up... stuff like that.
i couldnt see myself paying to have my car tuned, i am just the DIY sort of guy and WANT to learn new things, so the self tuning method was for me. and its paying off great!