This photo above shows 1/2 ounce of oak chips soaking in 1 ounce of Jamaican Rum. It can set in this state for a few weeks, months or probably years. I'm not quite sure what I'll do with it, but it will probably become part of a porter. I have a few 1 gallon carboys which work well with little experiments like this.
The rum will sanitize and add flavor to the chips. The combination of the two will bring flavors reminiscent of oak barrel aging to the beer. The entire contents, rum and all, can go into the beer usually during secondary fermentation.
I've seen stouts and other dark beers aged in oak. What other beer styles go well with oak aging?