From the info.txt (I didn't upload two blank pages BTW)

Artist name : GotoP (ごとＰ)
Webpage : http://www.mirai.ne.jp/~gotop/ - "Peeping P!"
Artbook name : School Girl
Color - 20 pages
Original release date : 2005 Winter

I (nicojull) scanned these at 600DPI using a low-end Lexmark printer/scanner
combo + Photoshop - once resized, the result looks a bit better...

If you're looking for more GotoP's goodness, I've torrented several of his CG CDs.
More info on my GotoP torrent topic :
http://www.hongfire.com/forum/showthread.php?t=43121

Visit DPG at http://www.animeartbooks.tk/
and #animeartbooks @ irc.irchighway.net