I do agree with most people on here, once a month is right for sending e-newsletters - and I like the facts about sending ones with free tips or programs you can download for for free!
my suggestions would be:-
* How YOUR business can help with potential client's businesses - i.e. social networking, tips on accounts/book-keeping, etc... you can also include audio, article links, etc...
* the hottest FREE program/website - this could be anything from PDF creator to creating invoices online - and saying that you can assist them if they have problems or they would like you to do it

* Latest company news [if you have any!!]
* then just a small blurb about the company...
HIH...

Julia