About the Premier Collection:

The Premier Collection is a series of high quality flight sim add-ons, delivered directly to you via the Web. As you know, you can find hundreds different add-ons in virtually every category of flight simulation. Naturally, the quality of these add-ons varies greatly from one product to another .... bla bla (Read the rest on their website)

Instructions:

1) Download the aircraft of your choice from : 
http://www.flightsimdownloads.com/premier/

2) Install it in the default directory (the setup program automatically finds the destination folder if you have the correct version of Flight Simulator installed)

3) Search for the file asreg01.dll (It is supposed to be in X:\Program Files\Microsoft Games\FS2002\MODULES\ if you have FS2002 installed) and apply the patch.

4) Run FS2002 and select the aircraft you've just installed. (There are many ways of doing it) Enter anything for the registration number in the popup window and click on "Register!". You're done!

5) Repeat step 4 for every new aircraft you install from the Premier Collection and all of them will be yours!