Nowhere in any publication does it say you need to hear "cleared into the bravo." All you need is an ATC clearance. If they tell you to climb to 3000 feet, and that brings you into the bravo, then you will fly into the bravo on an ATC clearance, and it is legal. The same goes with headings; if they instruct you to turn to a heading that will bring you into the bravo, you are following ATC instructions. It still never hurts to ask and get it on the tapes just to cover your ***. However, for your private pilot training and career as a VFR pilot, it's still considered a very sound practice to ask for and receive "clearance into the bravo" before you enter.