Back in May it was announced that the Canon 7D anti-aliasing/moire filter from Mosaic Engineering was being released, and there were plans to make one for the other cameras as well. We already know how well the filter works for the Canon 5D, but it was anyone's guess if they had fixed any of the issues with the original filter. Sebastian over at cinema5D takes a look at the filter and compares an unfiltered 7D in the video embedded below:
So to answer the first question, the filter works very well at reducing aliasing and moire. As you can see, it removes most of the aliasing/moire issues without completely destroying the sharpness of the camera (though Sebastian did add some sharpening in some of the shots). The filter seems to fix the wide angle issues that the original 5D filter had, and whether this is due to the smaller sensor is unclear. It's definitely a step in the right direction, and considering that the new T4i suffers from aliasing and moire just as bad as the original cameras that share the 18 megapixel sensor, it won't be too long before they've designed one to fit that camera to go along with the others they are designing for the T2i, T3i, and 60D.
Head on over to cinema5D to read the rest of Sebastian's list of positives and negatives about the filter. You can purchase the 7D or the 5D filter from the links below. The 7D filter will run you $325 and the 5D filter costs $385. It's certainly worth the purchase if you've got no other options for cameras and moire is ruining your shots.