I can concur with Hank. The printer will often want to manage it themselves to suit their workflow and even my local repro-shop prefers to do the imposing themselves. If you want to impose for your own purposes, exporting normally from InDesign and then imposing using an acrobat plugin or similar tool works just fine workflow wise.

Professional imposition solutions tend to be on the expensive side but there may be few alternatives if you have very demanding or specific needs. I've used Quite Imposing before when I worked for an agency but for the odd occasion that I need it myself, it is prohibitively expensive. One tip if you happen to work on a mac: a much more affordable program that has covered all my imposition requirements up to now is PDF Clerk Pro which has a special imposition module (and a polite and responsive developer) and works with PDFs and has saveable imposition schemes. Other options you may want to investigate are Indesign Imposition plugin (website seems to be down but still visible via google's cache) and Croptima Inplate, both of which say they are for PC and Mac (I have no knowledge of either). It's worth trying them out and putting them through their paces with an actual scenario (ideally a couple of different typical cases) before buying.

(sorry about all the editing, links keep on being ruined after editing)