Hi Guys/Girls

I just got my 3gs which i bought via apple about 3 weeks ago, came from china but by then i got transferred out of USA. now it finally caught up to me. i have a valid att account i already paid the first bill (even without a phone they billed me). So i will cancel my ATT account monday, but want to get it all working first. here is what i think i learned can someone review tell me if this is correct.

1. connect to itunes on my imac (currently 8.2.1 and osx 10.5.8) to activate with ATT card installed.
2. follow iclarified instructions to make copies of the ECID files for future upgrades.
3. change sim to Panama C&W, and run redsnow. but when i change the sim will it not say invalid sim and stop at that point? or just go forward and let it do its thing.
4. install source for cydia repo to run ultrasnow again with panama SIM.

then i am done with process and new sim works all features, and I will have push since i activated legal way, and copies of security files to upgrade later.

how do i upgrade to 3.0.1 or should i do that as step 1 (a) and then use 3.0.1 with redsnow?

thanks in advance for good advice.