Okay, I'm not sure if this is the right place to post this, but here I go anyway.
I just finished making a set of semi-photorealistic skin textures for a female avatar, and I'm releasing the PSD files (as well as some PNGs).
Because I always found the most frustrating part of starting out on SL was that I couldn't get my avatar's skin to look juuuust the way I wanted it. It's probably the most important part, along with shape, of making a unique and recognizable character.
The skin tone and lip colour can be adjusted via fill layers on the bottom of each image! Just double-click the thumbnail and it'll bring up a colour picker. This means you can make the tone, literally, whatever colour you want. Then add birthmarks/freckles/tattoos/scars/whatever (I'm going to put up a tutorial on that part soon).
Hopefully this encourages people to be creative! It's all free.
No artist permission or contact is needed if you want to use it, and they may be redistributed, modified, etc. The only catch is that I need to be credited as the artist of the base texture. =)
http://www.redmongoose.net/blog/2010/02/openskin-opensource-skin-texture-for-secondlife/
Have fun! <3