Messianic Christianity? I'm Clueless. Open Questions to The Realm.

Whenever I don't know something, I've been told the best thing to do is ask the Internet. Certainly, one can't go wrong doing that, can one? Better still, since I have a blog, I can put forth my inquiries to wiser people than me that come to The Realm of Possibility. Surely, I can arrive at some conclusions in here, my happy house. So here goes. I've got some questions about Messianic Christianity, if someone knows something about that. Hopefully, I've got that name correct as I'm really not even certain about that. This post could sound utterly and amazingly ignorant, but it wouldn't be my first one of those, nor my last.

Apparently, Messianic Christians are different in at least one respect, maybe a great many more, from Messianic Jews in that, well, they're not Jewish. Let me just get to my list of questions for those that might know:

1) Messianic Christians are non-Jewish persons that adhere to parts of Leviticus and the old Jewish Law? Why? I know some people that are involved in this denomination -- if that's what it is -- and they certainly aren't adhering to all of it. So... just select parts of the law. Is that correct? What is the reasoning behind this?

2) Also, is most of their "church" focused on trying to obey the Jewish laws and customs rather than on Christ? I know they celebrate the major Jewish festivals, feasts, and holidays, and they may or may not celebrate Christmas and/or Easter. Does anyone know about that?

3) They believe in Jesus... do they believe as orthodox Christianity does, that He is God, was resurrected, and through God's grace is the salvation given for all men and women? Do Messianic Christians believe following the law is part of salvation along with believing in Jesus?

4) At least the folks I know that are in Messianic Christian groups (and this is a small sample size, so I probably shouldn't generalize), they say they don't believe in preaching, as that's man telling the congregants how to live. They think God through the Holy Scriptures has given us what we need. Instead, they have instructors for their small group church. Is this how most Messianic Christians operate? And do I have right that they don't believe in the preached word? However, they're okay with teaching? Is that right? And most of the teaching is from the Old Testament, not the New?

I guess, just from what I've heard... well, I have a lot of problems with what I've heard, and it's a little concerning -- but, really, I am very ignorant on this practice and what Messianic Christianity is (who Messianic Christians are and what their intent is), and I'd like to learn a few things. If anyone knows something about it or if anyone is involved in it, please enlighten me. It would be much appreciated. Thanks.