Will be on a cruise in July, stopping in Warnebunde and we would like to have references for private tour to Schwerin.

Try this one and send them an email - I hope they speak English good enough. Insist on a fixed price.

http://www.flughafen-reisetransfer-taxi.de/

BTW, it helps if you write "Warnemünde" or "Warnemuende".

Thanks - we speak no German, so not sure this would be good for us.

...or you simply take a train to Schwerin and join a city tour there.

My husband and I took a Baltic Cruise for our anniversary and one of the stops was in Warnemunde. It was toward the end of our 14 day cruise, so we weren't in the mood to do too much. so we took a train to Rostock and just walked around there. They were having a market, which we enjoyed. Also, the church and the mall are somewhat interesting. We thought Warnemunde itself was a very cute little seaside village. Be sure to be on deck to enjoy all the locals and people on holiday waving and taking pictures of the ship as it leaves port.