I'm aghast at some of these responses.
The boy obviously has some sort of behavioural / social problem. Of course you should be worried and concerned about your child being bitten and you have every right to speak to the school about it, , but I am telling you now - going in all guns blazing will solve nothing.
What you need to know is what are the school doing to support - not punish - this little boy. He is 7 yrs old. He obviously has problems. It could be problems at home / poor parenting, but it would be very wrong to jump to this conclusion.
My DS has Asperger's Sybdrome and was a terrible biter until he was well into reception year. He is in Year 2 now and still lashes out (although no more biting) now and then if other children 'annoy' him. The difference with DS is that he has a diagnosis and support, a great school and other parents are very supportive and understanding. His last school struggled to cope, ended up basically locking him in a room with a TA at break/lunch time because they couldn't 'control' him and other parents 'complained' about my child. What was the result of that? We left the school. We were basically driven out. But it was a lose-lose situation, because guess what? Another little boy with challenging behaviour - which was eventually diagnosed as ADHD and ASD - joined the class in my son's place
Moral of the story: Children with behavioural problems need support, not chastisement. There are very, very few children in my opinion who are 'just little shits'. There is always a reason for aggression, and usually a good way to change the behaviour.