While I'm sure folks will assert that querying the database in any form is not allowed (i.e. will affect your Microsoft supportability), I will challenge them ahead of time to produce anything officially from Microsoft with such a statement. All kinds of stuff on inserting/modifying/deleting rows in tables and altering the scheme, but nothing on performing a select statement or executing a stored procedure that doesn't update the table contents in any way.
I will say that directly querying the database is something that should be done by folks that a) understand SQL and how it optimizes queries and b) understand the SharePoint DM. You don't want folks writing queries that will have a measurable negative impact on a farm's performance.
With that disclaimer out of the way, there is no OOB means of getting to this data via a published and supported API that I am aware of. You could get to it by stringing a few of the Social DB's stored procedures together, but it's kind of cumbersome. The following is a Select that will get you most of the way. You would still need to link it to your Profile DB to resolve the GUID to a profile name...you could alternately tzake the GUID and call UserProfileManager.GetUserProfile to return a reference to the profile and get the name that way.
FROM [Social DB].[dbo].[SocialTags] st
Inner Join [Social DB].[dbo].[Urls] u
On u.UrlId = st.UrlId
and u.Url = 'http://sharepointdev:9000/Shared%20Documents/Content_viewing_2011-07-26T131806.xlsx' -- the encoded URL of the file you want to retrieve Like It info on
Inner Join [Social DB].[dbo].[UserProfile_Validation] uv
On uv.User_RecordID = st.User_RecordID
InputTermLabel = 'I like it' -- or you can get the TermID for the "I Like It" tag and query against TermID
Not a perfect solution by any stretch of the imagination and one that will obviously require re-certification if any hotfixes, CU, or SPs are installed.