Watch out, riding is addictive. I started it to improve my hiking, and then all I wanted to do was ride.

Brick workouts are when you ride and then immediately go for a run. Before I got my tri shorts, I would leave my bike in the back yard, run into the house, change into my running shorts and shoes, then head back out the door as fast as I could. If you can run in your bike shorts, you can save the change and just have your shoes handy to head out for the run. It's not necessary to do a long run, just enough to get your legs used to the feeling of going from biking to running. For my sprint tri I would usually do a 10 - 15 mile ride (fairly hard), then run 1 - 2 miles. If I recall correctly, I think when RunningMommy was training for her Ironman, she would do a long ride (80 miles?) followed by a relatively short run (6 miles?). You may have jelly legs for the first 10 minutes or so of running, but it gets better after that, and the more bricks you do the easier it gets. Have fun! For some weird reason I really liked doing bricks.