Here is a listing of pic processor resources.

Chips

• PIC16F84 The apparent standard for small gadgets.  It has 18 pins.
  
• PIC16F84A The latest version of the most popular starter chip (above).
• PIC16F628 Another good starter chip.
• PIC16F87x A Recommended starter chip.
• PIC16F819, PIC18F252, PIC18F452 Recommended in Physical Computing.

 Compilers

    C (a quick comparison can be found here)

• Picc Lite ™ A nice free C compiler for Pic.  It has limited fuctionality. (limited free version)
• CC5X A nice free C compiler. (limited free version)
• CCS A well-known C compiler.  Somewhat costly.
• MPLAB C18 A well-known C compiler made by Microchip. (limited free version) .

    PicBasic

• PicBasic A compiler for the PicBasic language.
• PicBasicPro A compiler for the PicBasic Pro language.

Editors

• Jens' File Editor A free editor that integrates well with various C compilers. (free)

Programmer Software

• IC-Prog A free programmer. (free)

Programmers

• PIC-PG2 An inexpensive serial programmer.
• EPIC Plus A acclaimed programmer that is moderately priced.

Tutorials

• A great tutorial at Spark Fun.
• More tutorials at Spark Fun.

Other Resources

• http://www.epanorama.net/links/microprocessor.html
• http://www.ubasics.com/adam/pic/piclinks.shtml
• http://www.microchipc.com/