Facebook is making it much more difficult to post to a user's friend wall as an 'app' as it's been widely used to spam friends of users. While it is still possible, it requires extra permissions and a bit of extra work. If you still want help doing so, please let me know how you want to post to the friend's wall - is it automated, does your user initiate it and put in a message, etc?
Also, can we get access to their FB friends/address list?
Not really. With the Graph API v2.0 update, the only friends of a user that you can retrieve any information about is users that have also already approved your app. So, you'll be able to get that information directly from the user themselves instead of querying the friend of the current user's information. For more information on Graph API v2.0, see:
developers.facebook.com/docs/apps/changelog
I hope that helps explain,
Alex
How to post to another users wall?
