My friend is in love with a christian guy.. she wants to marry him without converting.. is there a way?

They can marry on whatever terms they so decide on between them. Will that satisfy those outside this relationship? Probably not especially with the families of either of them.

Go to a Justice of the Peace or any civil marriage. Religion does not enter.

Yes, she definitely can marry him without being convert. BUT, there should be a mutual agreement and understanding between both of them. And Specially, If the parents are OK with it. It will be good if they both talk about the consequences and changes they may face in their day today life Because of there different religion.

They also must discuss what religion they will be raising their children.

Yes, as J_9 suggested that's a very important thing to ask, because some family may allow a daughter in law to follow her own religion but they definitely would want their grand children to follow their own religion or which is father's religion. It usually happens in all religion. For example they may allow celebrating Diwali, but may not allow going to temple and do all the Hindu rituals. Hope it helps.