Looks bad. This is a link to NOAA's page on the storm.
Our thoughts go out to anyone in its path.
Update: The storm fell to Category 3 overnight from Category 4, but has the potential to rise during the day. Category 3 is still awful. Without checking, I believe Floyd, which devastated eastern North Carolina earlier this decade, was a Category 3, but it was a slow moving storm, which sat there for hours causing rivers to overflow their banks with rain rather than damaging with wind. Flooding of course, is the major threat in an area with as many open bodies of water as the gulf coast.
Further Update: Weather Nerd says that the storm weakened and became disorganized over Cuba, which is good news. His coverage of the storm is excellent.