I've also used the MX-1 mixer for stake conferences and for streaming a live multi-camera feed to remote locations for stake conference. It will do all the things mentioned by others. One thing I would add is that you can add a TM2000 Titlemaker CG unit downstream of the MX-1 for adding titles, borders, etc. You can do it on-the-fly, so there is no extensive up-front time required to build titles and text. If they change speaakers, hymns or prayers you can add them on-the-fly. It has a preview output, as does the MX, so you can build offline, then 'play' the CG live.
Both units are available on ebay still. I just had our school get the MX-1 and the TM2000 for use in streaming of school events, and I believe they paid well under $250 for each. I own one of each and use them for remote multi-camera field shoots. The usual tips apply; use only 75 ohm cable for the video feed. My personal preference for audio is to use an external audio mixer. Behringer makes some very inexpensive mixers that work verry well for these types of shoots. For miking, I take an audio feed from the chapel sound system and if a choir is going to sing I put up a large diaphragm condenser mic. The Behringer has phantom power, so it can drive any condenser mic. I have found that the ADK A51 mic is very adequate. It performs right up there with the more expensive mics, and it gives you an acceptable "panic" audio source if someone on the stand shuts off the podium mic during a choir number (yes, I learned that one the hard way..) Pro audio toys has them for a very reasonable rate.
Definitely download user manuals for the videonics products to get the full use out of them. Here are some links to a source for free downloads for these productshttp://www.lu-hilson.com/PDF/Videonics% ... Manual.pdf
(MX-1 manual)http://www.lu-hilson.com/PDF/Videonics% ... Manual.pdf
I've used both the s-video and the composite inputs, and mixed them (some s-video and some inputs composite) on the same live stream. for internet, the Videonics have plenty good quality.
I've also run across that converter issue w/ some VGA converters. Some converters sync rates are compatible, some aren't. Some can be used for 20 or 30 seconds before losing sync, so you can sometimes work around it. It's a good idea to have a camera ready to shoot the screen if it's a possibility.
I worked for 9 years as an audio/video engineer at a public access TV station, and these units are very robust for the price, and very capable of handling church A/V needs.
There are other solutions out there, but they are usually more expensive, and there aren't nearly as many still available.