The list of upcoming workshops is available in the Events calendar. You can subscribe to the gatk-workshop mailing list if you would like to be notified of upcoming workshops by email.
The course outline of our standard workshop formula is available here, and the typical schedule is here.
If you are interested in hosting a GATK workshop at your institution, have a look at this document which describes our requirements / expectations, then please email us at gatk-workshop@broadinstitute.org with some information about your institution and location, your needs and your desired timeframe for organizing the workshop.