My two year son is jelous of his younger sister and is very angry, I have tried spanking, time out, and nothing works. What can I do to break this?

Sibling rivalry. First, never leave the 2 of them alone in a room. Also, while your daughter is napping, give your son your undivided attention for 15-30 minutes daily (doing whatever he enjoys). While you're feeding the baby, your son can sit next to you & hold a book for you to read to him or you can sing songs together. He can 'help' you by bringing things for you. Praise him when he shows good behavior.
If you spank, he'll. hit. Model using words, like "Crying hurts my ears!" & tell him what IS okay to do when angry. Increase pleasant " time-in." When he acts out, immediately walk him to time-out from behind. Don't talk, make eye contact or look angry. Repeat till he stays put. Set timer for 2 min. His behavior will worsen at first, then stop, if you consistently ignore it by using time-out. Read " Little People." .
Put him to work. Kids that age can't differentiate work time from fun time as you do baby maintainance. They figure they own you & babies cutting in on their play time.If you enlist him as 1st assistant for diaper chgs/feeds/ where he brings the diaper/burp wrag etc he may get bored with the work component & leave to play. Private play time when babies asleep also works well. I agree with dr juster.
Agree. Dr. Juster's advice is excellent. Additionally, understand that with spanking etc. You are reenforcing the bad behavior. He want your attention, even if the attention is negative. The more attention you give the bad behaviors, the more bad behaviors you'll get. Rather, emphasize praising he good behaviors, and the bad ones will naturally fade away.
Scheduled one-on-one. First, understand that your toddler is having a perfectly "normal" reaction to the introduction of a younger sibling. I recommend scheduling one-on-one time with "mommy time" (and/or daddy time) on a regular basis, where it is just the two of you. Ask him what he wants to do with the time. Give him your undivided attention, as much as possible, during that time.
Sibling acceptance. Reassure your son that he is loved just as much. Spent alone time with him, at least 30 minutes a day. Also, letting him know that she is his "baby, " too helps to get his acceptance of the baby. Let him help with things he can handle. Spanking may make him more angry or jealous of her.