Most weeds are annuals and will die at first frost. I recommend just waiting til Spring and follow a good mechanical and organic weed management program. You can put down weed barrier in your beds but if you put any type of organic top dressing on top of the weed barrier, weeds are still going to grow.

The best prevention is a good weed management program. When the weather starts to warm up in the Spring, put down a pre-emergent. The rule of them is when the Forsythia start to bloom, it's time to put down the pre-emergent.

There are two kinds, granular and liquid. Granular must be water activated and non vegetative specific! In other words, they will kill any green herbaceous plant material (grass included!). It's best to put down the granular type in beds that are flat (no run off when then get wet!) Liquid pre-emergent is best used in other types of beds that don't need water for activation.

During the winter, you can get ahead of the weed problem by pulling up all the big weeds to get rid of the seed heads. Till the soil or let it set and put down a herbicide now if your ground is still warm enough for germination.

Preen has a good line of products for the homeowner. I'd stop by your local nursery and talk to the them. Or check out their website at http://www.preen.com/newpreen/prdpreen/index.jsp