How to add some icons like digg it,facebook it,linked in etc under the posts

I am seeing icons like "Bookmark using Digg it,facebook,twitter,linked" under the post of each entry.So if any users of my site sees it as useful they will just Digg it or bookmark it thus getting more SERP ranking.I am using wordpress.Is there any plugin available with wordpress for adding this?

 

Use social marker plugin. download it here http://blog.socialmarker.com/wordpress-plugin/

 

Now can my users be able to bookmark my site using various icons using this plugin.Anyway thanks for your reply,is there any other plug ins which I can drive my users into favouring which can significantly increase my SERP ranking?Between can you tell me how to upload the plug-ins inside the word press other than uploading it through the ftp?

 

you can try addthis it good for your blog

 

I tried that plugin,but the problem is,it asks for my user to manually bookmark my post and when he goes to bookmark the site he has to manually sign up for all the bookmarking sites.Or if he just hit submit will any of the bookmarking sites bookmark my post automatically/I am talking about the bookmarking sites in the social marker which do not require sign up?
Between I am looking for a plugin which contains 4 or 5 easy bookmarking sites icons where when visitors click on that it will be bookmarked automatically without having to do sign up and do manual submission each site one by one