I have a table that looks like this:

userid - action - date
10 - added - 2009-10-01
10 - xled - 2009-10-07
11 - added - 2009-10-02
12 - added - 2009-10-02
23 - xled - 2009-10-09

I want to return an sql query that will look like this:

userid - date_added - date_xled
10 - 2009-10-01 - 2009-10-07

if users have not canceled it would look like this:
11 - 2009-10-02 - NULL

I dont even know where to start??? i'm using php and mysql

Please help! and thank you in advance!