[quote=Nick]I am going to my first Catholic wedding this weekend, and I just wanted to know if there will be Communion. Is it a Mass?
It may be a Mass or it may not be. Catholics can marry in a nuptial Mass (i.e., a Mass that includes the nuptial liturgy) or they can marry in a nuptial liturgy that does not include a Mass. If a Mass is not included in the ceremony, there will not be Communion.
[quote=Nick]Many of my friends who are also attending the wedding are non-Catholic or fallen-away Catholics. Am I obliged to tell them that they cannot receive Communion, or should I leave that to the priest? Shouldn’t the priest assume that there are some non-Catholics at the wedding, and therefore make a general announcement about who may receive the Blessed Sacrament?
You are not obliged to tell anyone that they may not receive Communion. However, it would be a courtesy to point out to those who attend the wedding with you where they can find the guidelines to receiving Communion should Communion be included in the wedding liturgy. The guidelines can be found in the front of the missalettes that are usually kept in each pew pocket.
Although he is not required to do so, generally speaking, it is a good idea for a priest presiding at any Mass where there are likely to be a number of non-Catholics and fallen-away Catholics to briefly announce the rules for reception of Communion at the end of his homily. The bride and groom may request that he do so and may even print the guidelines for receiving Communion in their wedding program, but ultimately it is best for a priest to assume the responsibility to teach the congregation Catholic guidelines for reception of Communion. Presuming to take on such a responsibility yourself is not a good idea.