Hi! MOPS is an interdenominational Christian group for moms of preschoolers. You do not have to be a member at the host church to join. I do not belong to the group here, since the time doesn't work for me, but I was an active member of a MOPS group in Illinois. Ours did include prayer time and Bible study. We also ate, played games, made things, went out for moms' nights, had lots of playdates, and talked a lot about the joys and challenges of raising a family. You don't have to be a churchgoer to join, but you would want to at least be comfortable with Christianity, since there is a lot of God and Jesus talk.
And you need to be comfortable with your children learning Bible basics, too. At our MOPS group, the 2-and-up crowd had Bible lessons and playtime in a separate part of the church while we had our meetings. The under 2's had supervised playtime.
Our group included Catholics, Methodists, Baptists, Lutherans, Pentecostals, Episcopalians, non-denominationals, and "I'm not sures" - anybody who was open to Christian belief was welcome.
Some of our members were conservative, some were liberal, most were somewhere in between.
Personally, I found it to be a very supportive, friendly environment. I was a member for 2 years, when my daughter was 2 and I was pregnant with my son, then mother of a 3 year old and an infant. That's a time of life when a mom, especially one who is relatively new in town and far from family, can feel really isolated. It was nice to be a part of a group of women in the same stage of their lives, all of us looking to God and to each other for spiritual sustenance. Plus we had a really good time together.
Hope that helps clarify things.