What you want is an A/V receiver - for which there are many reviews on this site for various brands and tons of opinions. From $300 to thousands of dollars you can get excellent results.
In-ceiling speakers, of course, are typically one of the worst ways to do sound in a room. I also imagine that this is for a home theater, so you have a lot of homework to do on speaker placement, acoustics, etc. as well as a ton of research to do on which projector is good to purchase.
I consider, a decent low-mid level setup for front projection to typically run about $10,000 installed by others. A real entry level system can be had for about $5,000. A bottom of the line setup will run about $2,000. So, it is important to know where you fall within that budget range. Most people tend to be between bottom of the line and entry level... but expect mid-level performance. They won't get it, but you can have decent entry level results with careful planning.