FROM SMALLVILLE TO JAILVILLE! ACTOR SAM JONES WAS ARRESTED FOR CONSPIRACY TO DEAL MORE THAN 10,000 OXYCODONE PILLS!

One of the stars of "Smallville" was arrested this morning -- after cops say he was part of a conspiracy to deal more than 10,000 pills of oxycodone.
TMZ has learned Sam Jones, who played Clark Kent's best friend on the show, was taken into custody by DEA agents who claim Jones was a "co-conspirator" in a series of major drug deals in 2008.

According to documents filed in federal court, the DEA claims Jones was the "Hollywood connection" in a plot to illegally purchase and distribute the oxycodone.

Jones has been charged with conspiracy to possess with intent to distribute. He's due in federal court in L.A. later today.

If convicted, Jones faces up to 20 years in federal prison.