The best of the best human modelling tutorial is the Joan of Arc tutorial by Michel Roger. You can find an English version (if you can’t read French) at 3Dtotal.
You can view NateTG’s hair tutorial on pages 3 and 4 of this thread. In my opinion it’s the best strictly Blender hair I’ve seen yet.
You can also check out RipSting’s hair generator (Fiber 2.03, requires .NET), or the MakeHair script from the fellas at MakeHuman (requires AQSIS renderer).
For clothes, I don’t think there are really any tutorials on modelling them, but once you do you’ll find tolobán’s Transfer Weights script useful. You can find a link to it on page 2 of this thread (or just go directly to http://kokcito.tk/).
For specific parts of the clothing (not all of it!) you can also use softbodies to give it that flowing look. This requires a bit of thought though.
Finally, if you’re new to rigging you should do the 30 + 30 tutorial in the Blender Documentation. Nozzy’s rig is a pretty famous one for study around here, but it’s a little advanced for the newbie to comprehend at once. Look at it after you’ve got the basics down. Here’s a shameless plug for my action constraints tutorial, which you’ll need at some point (particularly if you want to understand Nozzy’s rig).