Diaper Pattern Reviews
There are dozens of patterns available online that can get you started.  We are always collecting links, so if you know of one I missed please email me!
Knitting patterns-
Aubrey Doodlepants- Adorable knit longies pattern described by the creator as a basic pattern.  Features a ribbed waist with drawstring and seed stitched cuff.
Baby Liberation- This pattern is designed to be felted once it is complete.  No pictures are provided, but it sounds interesting!
Curly Purly- A classic for all times!  This adorable soaker is well known and loved by many.  Excellent instructions and photos.
Dunmani- Knit some cute shorts with this pattern, a photo is included so you can see the finished product.
Knitting and Crochet.com- Basic instructions from a vintage pattern. 
Ottobre Designs- Ottobre Designs offers fantastic sewing patterns, and also offers this knit soaker pattern for free.
Pea Patch - Cute knit soaker with cuffed legs.  Lots of great pictures to keep you inspired.
Pimp my Longies- This tutorial for making knit longies and shorties includes lots of photos and a tutorial for those who are a bit more visual.
Punk Knitter- Cute pattern with lots of pics in completed and even on babies so you can see how it fits.  Don't be thrown by the adult content warning.
Tierr-verde- No pictures are included for this pattern, but the instructions are comprehensive and include information on selecting yarn.
Tiny Bird Organics- Adorable soaker with cute crochet ruffled leg openings.
Spray Family Knitting Machine Pattern- Written for the Bond/USM knitting machine.
Crochet Patterns-
Little Fire - Crochet pattern for both shorts and a skirty.