I saw your other post about ideas for working out. I know it's not kickboxing but have you thought about Taebo? Billy Blanks has a bunch of dvd's for Taebo (combines Taekwondo and Kickboxing). There is one that is called Billy Blanks Taebo Express. It has 8 10 minute workouts that I think would be helpful if you're trying to learn the basics yet still get a great workout. You can combine several of them and get an amazing workout (several of the workouts deal with the punches and the footwork). It's worth it to take a look. You should be able to find it at Walmart for about $10 (one time investment, totally worth it). Here's a link to his site: www.taebo.com/dvd/video/
I know it's not kickboxing directly but it might help.