Since SOL TRIGGER is a bit of an obscure game thus far (there is currently no word of it leaving Japan, to my knowledge), so I hope to make a list of some good resources here.

The Official SOL TRIGGER Site - Some great stuff here. I just love the artwork on the front page, and throughout, really. <3

Amazon.co.jp - Order the game from Amazon Japan!

The Officia Guide Book (Amazon Japan) - Get the newly released 160 page guide book! Has some great info on the characters, story, strategy, maps, and much more!

Mini-Soundtrack and Drama CD (Amazon Japan) - Currently out of stock. Check out the video above for a brief sample of 2 tracks from the drama CD.

Clear Files (Amazon Japan) - Two clear file set of the girls

Cute Mug (Amazon Japan) - Comes in two designs, either Ema or Sofie.

Sony PSP Accessory Set (Amazon Japan) - Comes with a cute, semi-hard case, a front cover, and 3 types of decoration stickers for PSP.

SOL TRIGGER Wiki (Japanese) - Not much info here. Has basic introduction on story and characters, and there are a few other external links to such sites as J.C.Staff, the animation company that made the animated sequences and a link to character designer Sokabe Shuji's (Persona 3 & 4) wikipedia page.