To add: Acts 20:5-7 seems to say that they gathered on Sunday for the breaking of bread; and the Didache speaks of a "Lord's Day" and not a sabbath, which would make more sense if it were a Sunday.
I'll post a couple of links on these from churches I do not go to. I ask all to read the content, and not just judge labels.
About the Sabbath:
http://www.sdanet.org/atissue/books/27/27-19.htmAbout Acts 20, 1 Corinthians 16:2, Revelation 1:10, Romans 14:5, Galations 4:9-11, Colossians 2:14 :
http://www.yrm.org/popular.htmAgain people PLEASE read the content and not just form labels on others. Point out where their logic is wrong and interpretations in context of their CONTENT.
http://www.yrm.org/sacrifice-qa.htm this specific page is stupid though. It says that at the kingdom the role of jesus will change, and people who haven't received him as salvation, until then, will have to start the sacrifices again, because his blood will not do anything. And it uses some scriptures from the old testament, to prove its weird point.