There's actually quite a few options out there, depending on your area, budget and who your shop affiliates with.
Oreilly's and BWD have been offering their Real World Training series for a long time now, and they're usually excellent. Price is somewhere around $100 for a four hour class evening, if I remember right. Most of the presenters are engaging and knowledgeable.
There's also ATG Training available, but not in all areas.

Check out the schedule on their site. Definitely go if you can. The training manual is included in the price, and the material is top notch.
ACDelco has also started offering classes in my area, but I'm less impressed with their material compared to BWD. Been to one NGK class, wouldn't mind going to more.