Internal promotion of training programs usually means finding inexpensive ways (read no outsourced printing allowed) to promote programs. I have found that a company's intranet and group email distribution can be great ways of promoting programs, courses and workshops.
You can be simple or fancy depending on how tech savvy you are. You can create an HTML rich email by using purchased software or web based applications that have templates. You may want to call it a training newsletter and use a template for a newsletter and produce a catalogue of training options.
If you have the technical support and capability to have an online information and registration page(s) on the intranet site, then that is a great option to not only promote the training offered but collect registration data.
If you offer courses or programs on an ongoing, quarterly or monthly basis a training calendar is a great option. A training calendar that can be updated easily with course descriptions and registration information will allow potential participants, HR and managers to look for dates that will work with schedules.
Keeping staff informed of professional development options is not only important to ensure numbers of participants in programs, it shows a dedication to staff development that can set an employer apart from the competition. In the current climate of increasing skill shortages, training and professional development of talent will be more vital then ever.