Most information about installing and using BlueZ are outdated, because the development of the official Linux Bluetooth protocol stack is making fast progress. The best information sources are the mailing list archives and the frequently asked questions.
Additional information will be provided BlueZ Wiki website.
Besides these documents various talks about BlueZ are available and in the most cases it is also possible to look at the slides and papers of these presentations.
A great collection of small and individual BlueZ related HOWTO's can also be found on the web pages from Marcel Holtmann. These HOWTO's cover basic installation descriptions, phone specific instructions or other Bluetooth related and important things.
The Bluetooth technology also supports cable replacement for TCP/IP based networks. The Personal Area Network HOWTO gives a detailed description how this can be done with Linux.