You can also attend a cat show in your area. The CFA and TICA could have shows close to you. The best thing to do would be to attend one of these shows, find the Manx cats being shown and talk to the breeders in person.
Here is the link to the CFA website:http://cfa.org/
And here is the link to the TICA website:http://www.tica.org/html/english/home/
Just go to the show calendar and you will be able to find the dates and locations of all their shows.