There is not much info on your profile, so...
Not knowing where you live I cannot give you a direct referral.
If you are staring a co-op here's some stuff:
How to Start a Cooperative
University of Wisconsin Center for Cooperatives How to Start a Co-op (these folks know how to do co-ops)
SEDG: Starting a Cooperative (http://www.calcooperatives.info/starting/ - broken link)
for financing /business edu
http://www.ncdf.coop/aboutncdf_new.html (broken link)
National Cooperative Business Association (http://www.ncba.coop/abcoop_howto.cfm - broken link)
...and a shameless plug for 'us'
"cooperative development centers"
Welcome to the Northwest Cooperative Development Center on the web!
Indiana Cooperative Development Center
Montana Cooperative Development Center :: (MCDC.COOP)
Georgia Cooperative Development Center
That ought to keep you for awhile