This website has hyperlinked cross-references and information on hundreds of dialects. Many researchers will find this information useful as it is all in one location.
On the main page are listed the main Chinese languages. Choose a language for a more detailed list of dialects. Most dialects have tone data, which is listed in master tone lists by language. There is also some tone sandhi data available. Some major dialects have complete phonological data available provided with IPA characters in charts that Chinese dialectologists commonly use. A tutorial is given how to read these charts.