Dream is a Japanese POP band. It first appeared on January 1st, 2000 when the large Japanese record company Avexnet (official web site in Japanese) held a contest to find the most talented young female singers. Three girls won the Grand Prize (in Japanese). They were chosen for their exceptional voices and talent.
When SPEED broke up in March 2000, the group Dream was created. Unlike other popular groups like Folder 5 or SPEED which had one or two main singers and backup singers, all three original members of Dream had main parts in songs. Today, this specificity remains. While the band was not considered very innovative, it quickly became very popular. One of their famous songs is "Reality" and a short clip can be found here (Windows Media Player 9 required). I would qualify their style as "Italian Disco Dance" but others believe Dream is closer to "Euro Dance". Regardless of how you wish to name the style, Dream is considered a "typical" J-POP band. Another famous clip "My Will" is available here.
On July 8th, 2002, Dream officially became an eight members band and the cover of their last album "ID" appears below. Their official web site at Avexnet provides a profile for every member as well as the traditional BBS and tour dates:
A special edition of the single "I Love Dream World" (from album "I World") was released as a DVD before Christmas and the video pictures the band singing under the snow. In Japan, it is not uncommon to see popular J-POP artists contribute to video games. "ID-Prologue-" was used in a video game which I cannot remember the name right now.
If you would like to listen to more sound clips, most of the band's production can be browsed here.