The October issue of Gamepro Netherlands has a rather extensive San Andreas preview. Here's a look over the new points:

• In one of the early missions CJ will be given the choice to wear the orange clothes of his gang. Doing this will earn you respect but you will be a marked man in enemy turf. Playing the safe way and wearing casual clothes won't get you much respect.
• When you buy new clothes, your old ones will automatically be saved in your safehouse.
• CJ will be customisable with beards and moustaches.
• A good selection of houses in the cities and towns will be enterable (and robbable).
• To start a robbery mission you will have to enter a furniture van and press R3.
• For a successful robbery you need to outfit yourself with ski goggles (enabling you to sneak around), and a furniture van where to load everything you are stealing.
• During a robbery you will be presented with individual items to carry out of the house into your van, one by one. When you're done, drive on to a courier who who you will sell the stolen merchandise to.
• Drives between cities take at least 15 minutes.
• It will take several minutes to drive only halfway up Mt. Chiliad with a dirtbike.
• Underneath Mt. Chiliad there is a tunnel.
• An advantage of training in the gym will be that you can hit harder and climb better.
• CJ will be able to climb around obstacles and fences in the same manner as Lara Croft in Tomb Raider. He will be able to hang onto ridges and pull himself up.
• If you get too heavy training for muscle, you will run slower.
• Experience with weapons will increase your accuracy with every weapon. (Not only the deagle as we've heard before)
• Every gang will have a favourite car that you will see them driving around in.
• Leaving cars on the street will get them towed, and you can steal them back from the impound yard.

Related link: GTAForums topic.