on this subject, hopefully, it exists a lot of site really more serious than the funny zany links of gda.
1) About the sumerian civilisations writings, myths and legend :
http://etcsl.orinst.ox.ac.uk/cgi-bin/etcsl.cgi?text=all&charenc=j#
2) About the babylonian and akkadian civilisations writings, myths and legend (including Gilgamesh) :
http://hudd.huji.ac.il/ArtlidHomepage.aspx
3) About the kassites writings
http://oracc.museum.upenn.edu/ckst/
4) About ancient mesopotamian writings and religion
http://oracc.museum.upenn.edu/cams/
http://oracc.museum.upenn.edu/amgg/
http://oracc.museum.upenn.edu/cmawro/
5) About Assyrian writings
http://oracc.museum.upenn.edu/nimrud/index.html
http://oracc.museum.upenn.edu/rinap/
http://oracc.museum.upenn.edu/saao/
http://oatp.net/Download_texts/downloadtexts.html
6) About hellenistic mesopotamia writings and religion
http://oracc.museum.upenn.edu/hbtin/
7) About Hittites writings (in german)
http://www.hethport.uni-wuerzburg.de/CTH/
http://titus.uni-frankfurt.de/texte/etcs/anatol/hittite/cthtr/cthtr.htm
8) About persan writings :
http://titus.uni-frankfurt.de/texte/etcs/iran/airan/apers/apers.htm
Sans oublier un catalogue assez fourni concernant toutes les périodes historiques, et nottament celles qui nous interessent ici :
http://legacy.fordham.edu/Halsall/index.asp
a blog regularly updated about an impressive amount of university work available about this period :
http://ancientworldonline.blogspot.fr/
Et pour ceux que cela interesse un repertoire des productions mathématiques en cunéiforme de ces périodes :