It was easy. I just followed a BlackRa1n tutorial available from my friends at the iPhone Download Blog. My carrier is AT&T so I didn't have to unlock.
I downloaded Cydia and Rock listings for jailbroken iPhones. Since Cydia is the more popular one, I stuck with that for my initial customization.
I downloaded Categories, Winterboard, Cycorder and Qik.
Here's how the first page of my homescreen looks:
The theme is called Blue Thunder and it put in all those wonderful icon replacements. The Wi-Fi icon is replaced by the Apple logo and the Acura logo replaced the AT&T logo.
This is my lock screen. It's an Acura TSX, which I am leasing (and will eventually purchase). The brighter the headlight, the stronger the battery life. The target on the bottom is where I swipe to unlock the iPhone. When you swipe, a fingerprint appears which is a nice touch.
I added everything I want to for now. I'll take this jailbreaking thing slow. I'll share good stuff I find in Cydia or the Rock on this blog.