i would recommend not upgrading unless you have severe memory problems. you won't notice a dramatic difference in performance. there are much better ways to speed up your computer.
that corsair memory should work with your motherboard. the mobo specs say that you have 4 slots total. there is a max of 2GB installed memory so i assume you can have 512MB maximum you can install in each slot. i am going by what Dell says. this is your computer correct?: