centos server's mysql version's problem

[Yang Yang]

hi,i am a new guy for a company,and will make 1-3 server to mysql datacenter

i have 2 question want to ask and hope receive responce

1.on centos or linux server,i should use 5.0 version or 5.1 version,which
verison is better and can resolve many traffic use php+mysql

2.the my.cnf should i configure or where i can find some information?

thanks all ,hope receive responce