How to get user information from sharepoint site to my webpart

I want to developed a webpart that get all users information with user images from sharepoint 2007 site. Please suggest me how can 开发者_如何学JAVAachive this. Is there any webservices that can i use in my custome webpart? Please suggest solution for the same.

Thank you.

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You can use the UserProfileService to get user details. Details about the same for SharePoint 2010 is here.