Microsoft SharePoint offers a web service to query and use to simplify jobs that typically you’d have to need a connection to active directory.
Some Basic URLs:
http://(Your SharePoint URL)/_vti_bin/UserProfileService.asmx
http://(Your SharePoint URL)/_vti_bin/Lists.asmx
http://(Your SharePoint URL)/_vti_bin/UserGroup.asmx
From within http://(Your SharePoint URL)/_vti_bin/UserProfileService.asmx you can pull these details
UserProfile_GUID, AccountName, FirstName, LastName, PreferredName, WorkPhone, Office, Department, Title, Manager, AboutMe, PersonalSpace, PictureURL, UserName, QuickLinks, WebSite, PublicSiteRedirect, SPS-Dotted-line, SPS-Peers, SPS-Responsibility, SPS-Skills, SPS-PastProjects, SPS-Interests, SPS-School, SPS-SipAddress, SPS-Birthday, SPS-MySiteUpgrade, SPS-DontSuggestList, SPS-ProxyAddresses, SPS-HireDate, SPS-LastColleagueAdded, SPS-OWAUrl, SPS-ResourceAccountName, SPS-MasterAccountName, Assistant, WorkEmail, CellPhone, Fax, HomePhone