You might want to consider this

Trevor
Loudon,
a New Zealand-based libertarian activist, researcher and blogger, noted
evidence that “Frank” was Frank Marshall Davis in a posting in March of 2007.
Obama’s
communist connection adds to mounting public concern about a candidate who has
come out of virtually nowhere, with a brief U.S. Senate legislative record, to
become the Democratic Party frontrunner for the U.S. presidency. In the
latest Real Clear Politics poll average, Obama beats Republican
John McCain by almost four percentage points.
AIM recently disclosed that Obama has
well-documented socialist connections, which help explain why he sponsored a “Global Poverty Act” designed to send
hundreds of billions of dollars of U.S. foreign aid to the rest of the world,
in order to meet U.N. demands. The bill has passed the House and a Senate
committee, and awaits full Senate action.

Full article here; http://www.aim.org/aim-column/obamas-communist-mentor/

Frank Marshall Davis.................
In June of 1950, a person Frank Marshall Davis was trying to recruit into the Communist Party revealed to the FBI, that his interest in the Party went back to 1931 with the Scottsboro and Angelo Herndon cases.
Certainly from the mid/late '30s to the early '40s Davis was involved in several Communist Party fronts including the the National Negro Congress, the League of American Writers, the National Federation for Constitutional Liberties and the Civil Rights Congress.
The FBI first began tracking Davis in 1944 when they identified him as member of the Communist Party's Dorie Miller Club in Chicago-card number 47544.

 http://www.keywiki.org/index.php/Frank_Marshall_Davis