They are still available, but you will probably never see them at a big box store or tactical centered gun store. Winchester still offers them in the silver box line. Any full service gunshop should be able to order them for you. You might try Mid-South or Natchez online, but you will pay a fee usually and shipping costs.
Midsouth MAGTECH AMMUNITION & COMPONENTS .38 SPECIAL 148 GR. LEAD WAD-CUTTER 50 RDS Midsouth ULTRA MAX AMMO 38 SPECIAL 148GR HOLLOW BASE W.C. LEAD 50 CT REMANUFACTURED Pistol, Rifle, Shotgun, and Rimfire Ammo - Natchez Shooters Supplies