Porn legend Jenna Jameson just pled "guilty" to DUI -- but the good news for her ... she won't face any jail time.
TMZ broke the story ... Jameson was arrested after a single-car accident back in May in Orange County -- and was subsequently charged with DUI ... drugs and alcohol.
Jenna was also charged with driving without a valid license -- but that count was dropped today in exchange for her guilty plea.
According to law enforcement, Jenna blew a .13 and had two prescription drugs in her system at the time of her arrest -- zolpidem (Ambien) and buprenorphine (Suboxone).
Jenna was sentenced today to 3 years informal probation -- and was ordered to participate in a 3-month alcohol education program, as well as the MADD (Mothers Against Drunk Driving) program in O.C.