Replicating mysql DB to local machines

We have an application written for a PDA that we are switching from MS
Access to Mysql. There is a central server that has all the data in a
mysql database, however when we sync from the PDA it is much faster
sync'ing to a local copy of the mysql database then on central server
(users are remote and must VPN into server).

What are the options for taking a larger mysql database and segmenting
out data for a particular user (a subset of total data) to their local
machine? Is mysql replication a good option or is there some other
technique?