There are at least two groups using this name:
1) ｃａｐｓｕｌｅ (Japan), an electronic duo on their own label, Contemode.
2) Capsule (Miami, Florida), a hardcore/screamo band currently signed to Robotic Empire. 1) capsule is an electronic duo, formed in Kanazawa, Japan in 1997 by Yasutaka Nakata (co-producer, art director) and Toshiko Koshijima (vocals). They are part of the shibuya-kei movement that started in 1990, most notably by Pizzicato Five.

Read more about Capsule on Last.fm.