Lots of good suggestions. One I'd add would be a Facebook Group (see FB link in my sig). We use it to organize pickup games, remind each other about league nights, talk lists, gab about new releases & rumors, etc.
I run our local X-wing group and am responsible for setting up the regular play nights, and (starting next month) I will be running the tourneys, leagues, & other one-off events at the store. I am not the store owner, but I work with him constantly on what works best for his schedule, what he wants to see from the local group, etc, and he works with me about what he can do to better support the local players, including stock, prize support, play space, etc.
If you can find a competent, dependable individual to do this for you, great. If not, I think it would pay off for you to take the reins on your own for a while, until your local group grows enough that the right person emerges who can take it over for you. Please note -- I think it's very important that you don't just tell the first idiot who volunteers to go for it, especially if he/she will be running events. Ultimately, this person will be representing you and your store.
Whatever happens, having someplace where your customers can get together to talk & set things up should be pretty beneficial to getting things moving in your shop. As much as I detest facebook, lots of people use it, and it's a great tool for organizing gaming groups.
Best of luck!