Third parties of good. But nothing should replace your effots to consult the manufactures documents of examples, techniques, and application notes (redundant on purpose).
Nigel's tutorials aren't the only one's out there on the net. Spend a little time on google. There's more out there than you could possibly read in months. Dive in and get your feet wet so to speak.
Have you yet committed to a microcontroller? It may be a good idea to start out with only one manufacturer so that you don't get bogged down in the differences between them. Most will give free samples, just not all to the same places. Also, some have better support than others.