Ina Centaur has created for us an absolutely amazing collection of different high quality skins and outfits for the benefit of Open Sim worlds. They are released under the creative commons Attribution 3.0 Unported licence.
Here is the website address to take a look.http://osavatars.com/
The main site is not fully operational yet, but she has provided a link to download the entire collection here.http://osavatars.com/dev/OSAvsSpring2011.iar
Download the file, put it in the same directory as your sim and while your avatar is logged into it, type:
load iar firstname lastname destinationfolder yourpassword OSAvsSpring2011.iar
I have put a small selection at Wright Plaza 2nd Floor for those who dont have sims.
Be sure to give some feedback on her website!