If you read the latest version 3.3.4 supports multi threaded access.
2006 February 11 (3.3.4)
* Fix a blunder in the Unix mutex implementation that can lead
to deadlock on multithreaded systems.
* Fix an alignment problem on 64-bit machines
* Added the fullfsync pragma.
* Fix an optimizer bug that could have caused some unusual LEFT
OUTER JOINs to give incorrect results.
* The SUM function detects integer overflow and converts to
accumulating an approximate result using floating point numbers
* Host parameter names can begin with ‘@’ for compatibility
with SQL Server.
* Other miscellaneous bug fixes
2006 January 31 (3.3.3)
* Removed support for an ON CONFLICT clause on CREATE INDEX -
it never worked correctly so this should not present any backward
* Authorizer callback now notified of ALTER TABLE ADD COLUMN
* After any changes to the TEMP database schema, all prepared
statements are invalidated and must be recreated using a new call to
* Other minor bug fixes in preparation for the first stable
release of version 3.3
2006 January 24 (3.3.2 beta)
* Bug fixes and speed improvements. Improved test coverage.
* Changes to the OS-layer interface: mutexes must now be
* Discontinue the use of thread-specific data for out-of-memory
2006 January 16 (3.3.1 alpha)
* Countless bug fixes
* Speed improvements
* Database connections can now be used by multiple threads, not
just the thread in which they were created.