First PIC microcontroller family to learn? and resources? development board?
I am thinking very much along the same lines as Wouter.

Don't bother with the PIC16 and below unless you have real cost/space reasons to use them.  Yes, they have their place, and they are good top play with, but they are considerably less usable than the PIC18 series, and not much cost difference.

The PIC18 is a good starting point.  Everything you learn on the PIC18 can be easily translated upwards to the PIC24 and the dsPIC series.  The core operation is the same - just the number of bits and some of the peripherals are different.

And as for a development board?  How adventurous are you?

If you don't mind using breadboard, then a development board is pointless.  Most of the PIC18 chips (and PIC24/dsPIC) are available in DIP packages, so you can just plug them direct into breadboard.

All the PIC18 chips have internal oscillators, so there is no need to worry about external crystals, and stray capacitance, unless you have very strict timing requirements (for example USB).  You can make a functional system with just a PIC18 and a couple of decoupling capacitors.

You will, of course, need an ICSP programmer.  I use a clone of the PICKit2, which is quite cheap, and with a 5-pin header (or 5 wires) you can program the PIC direct in the breadboard.

Another great thing with the PIC chips are the free samples you can get as long as you don't have a hotmail/gmail/etc email address (i.e., corporate or educational users).