i have a VPS server which im leaving this company becasue of excessive downtimes. im migrating to anew host, the system is the same and the same operating system(centos 4). whats the best way to migrate to the new system? im trasnfering over apache2, php5,mysql5,BIND, and postifx.

the most important things are bind and postfix. which are also probably the hardest things to do.

i run my own DNS and mail server for my domain, and during the time it takes to tranfer i do not want to have any emails sent to me not delivered.

well there is no best way really, you just move things across one piece at a time. if you have a large amount of dependencies of serving and data etc... then you'll need to move things across more, but things like mail, just put your new server as a lower MX number than the currnet one and that will start recieveing all new mail when it is available. outside of that just get the new box up and running and then swing DNS across etc... you may want to run a subdomain , e.g. newserver.example.com for the ew servers whilst you prove them with test data.