Part of what makes HIV such a nasty virus is that it attacks our immune system, which is what we have around to keep viruses from attacking us. We may have just figured out how to keep HIV from exploiting our immune response, meaning that our bodies could fight it off just like any other virus.
When HIV enters your body, one of the first things that it does is incorporate a special type of cholesterol into its outer membrane. It steals this cholesterol from one of our immune system cells, called a plasmacytoid dendritic cell, or pDC. pDCs are the cells that first recognize the HIV virus, and they're supposed to instruct other parts of our immune system (like T-cells) to go after it, but once HIV has stolen the pDC cholesterol, it can "reprogram" the pDC cells so that they don't do their job, screwing up our entire immune system and allowing the HIV to spread.
Most vaccines work by teaching T-cells new ways to attack viruses, but with HIV, that approach isn't as effective, since the T-cells themselves have been compromised by the reprogrammed pDC cells. A research group at at The Johns Hopkins University has discovered that it's possible to attack HIV before the virus is able to mess with the pDC cells, by simply disrupting its stolen cholesterol membrane. Without this membrane, the virus can't mess up our immune system, and our bodies are then able to attack it like a normal virus, effectively preventing HIV from causing AIDS.
At the moment, researchers have this working in the lab, which I take to mean that it's effective in a petri dish. The next step will be animal trials, followed by human trials, which could lead to a vaccine that fights HIV and prevents AIDS.