Thus, we see that Apple is now selling a microUSB to Lightning (its new dock connector) adapter. Sadly, it's only selling that adapter in European stores (such as, for example, its U.K. online store).
In the U.K., the adapter will sell for 15 pounds ($24) and ship within three days.
So, those who might want the convenience of using their microUSB cables with Apple's Lightning adapter are out of luck, although people can always buy directly from one of the European stores, which is a pricey proposition with VAT.
[Apple also sells a 30-pin to Lightning adapter.]
The most likely way for these adapters to become available for those outside the E.U. is that old familiar auction site, eBay. We anticipate that it is only aa matter of time before adapters begin showing up on eBay. We also expect that it's only a matter of time before clone adapters begin showing up, as well.
You might ask why Apple didn't just adopt the microUSB standard. For one, Apple likes to go its own way. Cynics might add that the adoption of a proprietary adapter means additional revenue for the company with sales of these sorts of adapters.