I feel bad now

I only had one code for GAF. I will distribute a promo code through Twitter in about 9 hours from writing this post (11 pm GMT+3). Follow @onemorecoin for that, and feel free to unfollow later. It's an Arabic account and you don't have to torture yourselves by following it. The giveaway will be in English just for you guys. Hope everyone's happy now!
Now, I do have an important question. I have a 3GS, with tons of apps and games. What's the proper procedure for migrating to iPhone 4? Will I lose anything in the process? For example, will I keep my progress in Angry Birds and my Canabalt highscores, etc?