I really think you shouldn't shy away from reading the User's Guide once in a while. For the most part it's wel written, highly informative (like any User's Guide should be, obviously), relatively easy to comprehend and it can even be considered a "good read".
That said good tutorials on basic non-ICE related subjects are getting sparse. Luckily old tutorials for the most part are still valid (only the ones talking about the old (pre-ICE) particle system can be safely ignored (as this "legacy" system was removed from SI recently).
Some of the older stuff on Passes can be found in this thread - VAST - XSI Learning Movies on YouTube
, which still is IMHO an unsurpassed training resource (but, like a said before: ignore the particles).
This thread - Softimage XSI 4 Principles DVD on YouTube
- has some videos about passes also.
And while you're at it, make sure to check out the rest of our Tutorials forum