Fun thread. I love watch watchin' guys throw down some slap grooves. I can hardly look away.
I bought the "Slap It" and was initially slowed by the lack of tab as well. Determined to figure this stuff out, I made photo copies and wrote tab-like notes around it. I spent a number of weeks really focused on learning it.
In the end, I really enjoyed workin' it out, and I recommend these lessons to anyone. In fact, after learning 10 or 12 of the mid to advanced lessons, I was inspired to come up with my own composition. I worked it up over a series of weeks, bought an inexpensive 8-track with built in drum machine and recorded it. I then overdubbed some accompaniment instruments (guitar, keys). You can hear the result here: Link Removed
I didn't directly lift any of Tony's licks, but the style is quite similar.
As others have said, you start slow and simple, practice and move forward. I wasn't new to bass and had some simplistic slap skills before starting this, but didn't know how to practically apply it.
In spite of the missing tab, the combination of CD and written music allows you to go at your own pace and really study the details. It is an effective approach I thought.
Best of luck, Daren