I have always felt that a lifelong technical career in IT was next to impossible, as new technologies and methodologies come online you would need to be very diligent in constantly updating your skills to remain relevant. Personally I look forward to moving into management someday, if for nothing else other than to step off of this treadmill.
I do however maintain an active interest in learning about new technologies, and read technical books on programming and databases constantly. Strangely enough, this is often not the case with many of my peers in IT who actually want to stay technical, but I never see them making an active effort to learn new technical skills outside of the narrow scope of their existing jobs. It seems to me that for some developers, they stepped off that learning treadmill the say they left college.
So is it possible to start working as a developer at 22, and still be one when you retire at 65? This post has some really interesting comments on the subject, I encourage you to read Greg's comment in particular if you harbour ambitions of being a life-long developer:
Updated 2021 : note that the above post was originally published in 2007, but is left here for archival purposes.