What are some good ways of marketing a Bitcoin related service to Bitcoin users? What is a brief summary of some good ways of promoting a Bitcoin related service? This could include:


Bitcoin Service Directories
Forums
Advertising
Mailing Lists
???


The target audience is people who have bitcoin and know how to use it.

To avoid this question being too broad and requiring answers that are too long, I suggest keeping any summary of each item brief.
The folks at bitcoin.it run a moderated listing, https://en.bitcoin.it/wiki/Trade, which you can list at.  Another way is to work directly on reddit (r/bitcoin) and http://www.bitcointalk.org/.