moving servers and mysql dbs We have a number of websites using mysql dbs. We are moving these sites to a new server. We also moving the dbs to a new server seperate server. To make this easier we have setup master slave replication. 

The question is as we start moving the sites to the new server is there any problem with the using the slave db until we have moved all the sites across and can turn off the master?
No issues with using the slave DB if you are ok with having the site in read-only until the cutover.

You could turn the READ_ONLY=1 in my.cnf (set global read_only=1) in the slave just to make sure there are no unintentional writes to the slave.