301 Redirect Using htaccess

Hi

We are trying to maintain my friends webpage in a SEO friendly way because he is living problems with google regarding to same content problem in many pages.We have both both german and english content in 4 domains so we decided to use 301 redirect with htaccess so his position in google wouldnt be affected.

We want to transfer german contents to the site ending with .de and english content to .com

for example

http://www.domain.de/en/search/index.php
http://www.domain.com/search/index.php

http://www.domain.biz/en/search/index.php :
http://www.domain.com/search/index.php

http://www.domain.com/de/search/index.php
http://www.domain.de/search/index.php

http://www.domain.biz/de/search/index.php
http://www.domain.de/search/index.php

http://www.domain.biz/en/index.php
http://www.domain.com/

also we want to redirect in the same domain..

for example

http://www.domain.de/de/search/index.php
http://www.domain.de/search/index.php

http://www.domain.com/en/index.php
http://www.domain.com/

I am new to this rewriting and redirecting issue so i would be pleased işf you can help me
Do I need to redirect all pages 1 by 1 using redirect 301 or is it possible to make it by using
rewrite ?

I would really appriciate any help

Cheers

Onur