I’m not sure if you’re willing to take it this far, but since you are showing the enthusiasm and ability to create this card, you could also create your own personal web page, blog, myspace page, or whatever.
You could then add a link to this on your card as well.
This way when you obtain new and useful information in the future, instead of printing up a new card you could just update your page.
I did that with
www.sitelane.com so when people ask me for ebook information, I just send them to that site.