I'll mention it in my next attendee email blast for Strange Loop and if you have some fliers, you can put those out too. I wish there was a better place to centralize all the St.Louis tech events. I'm tempted to put up a site for it in fact. I think best advertising is to focus on user groups and Twitter - that's where you can hit groups of developers.
I'm happy to help with finding sponsors although in my experience it's helpful to have something concrete to ask for and an explanation of the value to the sponsor (what is the audience, expected attendance, event particulars, where sponsorship goes, etc). If you're collecting money I would recommend either having sponsors pay for a specific thing (shirts, food, whatever) and preferably pay them directly OR it
might make sense to actually incorporate and form a non-profit org if you think this will be an ongoing thing such that having a legal entity would help. Once you cross a certain $ threshold, sponsors typically want to pay via purchase order which requires a federal EIN number and a bank account. Incorporation costs about $160, the EIN request is free. Happy to help with that. I would recommend setting up a registration site on http://eventbrite.com so that you can have someplace to point people and start gathering registration info. Would be good to put up a simple web site / wiki too.