Falcon is a new transactional database engine that is still in alpha and will be one of the huge features in the MySQL 6.0 release. Since they are wiping the slate clean, they are building the engine from the ground up to fully maximize use of today’s 64-bit multi-core computers.
One of the big features is the very cool true Multi Version Concurrency Control (MVCC) system allows tables or records to be updated without having the overhead of locking rows/tables.
The database supports a number of modes including: consistent read (I’m assuming this is read uncommitted), InnoDB emulation, and read committed. There are a ton of other features that you should check out.
They hope the engine will be ready for public consumption by Q1 2008, but that is certainly subject to change.