This thought went through my mind many a times since June this year, when my iPhone 3GS's 1 year warranty expired. My son has a iPod Touch, which he jailbroke (still within its 1 year warranty period), for reasons only a teenager can understand. One thing that caught my eye was he could change the themes on the iPod Touch. He was also excited that flash could be played on iPod. As the internet has a lot of content using flash, I thought maybe the time has come to jailbreak my iPhone.
Using the Jailbreakme website is probably the easiest way to jailbreak an iPhone. The experience of jailbreak process itself is virtually painless. However, be warned that a jailbroken iPhone may not be beneficial for those who use their iPhone for nothing more than checking e-mails, browsing internet, playing games, listening to the iPod or taking occasional pictures or videos.
My experience of using a jailbroken iPhone is not very positive. Though changing themes is a doodle, but getting flash (or frash) to work on iPhone is still a hit or a miss. Most of the apps on Cydia and Rock are paid, thus, I don't see a compelling reason for jailbreaking. My personal feeling is people jailbreak their iPhone/iPods for kicks and probably, it gives them the sense of freedom to try stuff that one might not be able to do with the unjailbroken iPhone.