This article is from the Ethernet FAQ, by James Messer James@NetworkUptime.com with numerous contributions by others.
From a functional point of view, switching is exactly the same as
bridging. However switches use specially designed hardware called
Application Specific Integrated Circuits (ASICs) to perform the
bridging and packet-forwarding functionality (as supposed to
implementations using a central CPU and special software).
Consequently, switches are much faster than bridges.
Ethernet switches also offer additional capabilities such as virtual
LANs (VLANs) and full duplex connectivity.