1. Facing Sherman in South Carolina: March through the Swamps by Christopher G. Crabb (The History Pr, 2010).
This book covers the entire Union march through the Palmetto State, covering the skirmishes in the swamps and along the river lines in Sherman's path. There are a lot of great modern photographs of the ground described, but, sadly, no maps at all.
2. Charleston Under Siege: The Impregnable City by Douglas W. Bostick (The History Pr, 2010).
Looks like a capable introductory work on the subject, with the usual suspects such as the firing on Fort Sumter, the 1863 ironclad and Fort Wagner assaults, the Hunley saga, and the abandonment of the city in 1865.