|| OAVs & Drama CDs ||

'So,' you say, 'what's with the non-manga info?'

I haven't been able to find this information on any English page, so up it comes. This is courtesy of the following Japanese sites:
K2-Forum
Character Voice Database Page
Seiyuu Database WWW Version

Voice Actors
I'm fairly certain that the OAV voice actors also did the Drama CDs.

Atsushi - HIYAMA Nobuyuki 檜山 修之
Junichi - MATSUMOTO Yasunori 松本 保典
Kouji - IWATA Mitsuo 岩田 光央
Masami - NANBA Keiichi 難波 圭一
Masayoshi - INOUE Kazuhiko 井上 和彦
Tooru - HORI Hideyuki 堀 秀行
Yuriko - OKAMOTO Maya 岡本 麻弥

Drama CDs

There are five. All are dialogue only, no singing. About 3000 yen.

Cover images from K2-Forum.

Kusatta Kyoushi no Houteishiki
Movic M-013 Released: 94.1.1
Kusatta Kyoushi no Houteishiki 2 : Hawaiian Drama, Love and Ambition's 6250 km
Movic M-023 Released: 96.12.1
Kusatta Kyoushi no Houteishiki 3
Movic M-026 Released: 98.3.1

Cover images from Marine Entertainment site.
Kusatta Kyoushi no Houteishiki ~You are my treasure~
Marine Entertainment MMCC-3026 Released: 02.8.23
Kusatta Kyoushi no Houteishiki ~Like a dream; like love~
Marine Entertainment MMCC-3027 Released: 02.9.26

OAVs
There are two, each 30 minutes long. About 6600 yen.

Cover images from K2-Forum.

Original Soundtrack

Cover images from K2-Forum.