Advice on using LinkedIn for authentication

hi We run a number of (mostly open access) websites on .net. We would like to move to membership access for certain features and would particularly like to use LinkedIn as a means for people to log in to our site (the audience is busy professionals who will already have linked in profiles). I would be really grateful of any advice on how easy/reliable/desirable this is. Our aims are to use the basic account details (name, job, picture) from LinkedIn, then to keep additional info on our site (Content preferences, memberships etc). Would we create a .net user for the individual the first time they come? Have many sites deployed this kind of feature? And finally is there anywhere where we could hire knowledgeable professionals to implement this? Comments on any or all of the above would be greatly appreciated! ...