Samsung has a pair of new dual SIM "micro" sized phones. Well, they are micro sized in a world where 4.3-inch phones are being given the moniker "mini". The offerings are the Samsung Galaxy Young S6310 and Fame S6810. Both phones run on Android 4.1.2, Jelly Bean.
I wont beat around the bush. Priced at Php5,490 for the 3.27-inch Galaxy Young, and the Php7,500 for the 3.5-inch Galaxy Fame, it is really hard to recommend these phones. It is not just the size of the displays, but their resolution. Both phones come with low resolution 320 x 480 displays. Behind the displays, the situation is not any better with single core processors.
Unless you want a really small device there are better phones for the same or less money. If you want a smaller device from a major manufacturer, I would recommend the Huawei Ascend Y300 instead. For Php5,490 you get a 4-inch, 480 x 800 pixel resolution, display and dual core processor. If the dual SIM function is important, the Php3,990 Cherry Mobile Flare (now updated to Jelly Bean) would be a another more interesting alternative.