I currently opperate two websites. www.theoriginalblindman.com and
www.houston-hunterdouglas.com - How and when does google search for
backward links. And how long does it take to be updated in Google?

Googles search bot -Googlebot- scans your page for other links. So if
you place a link to your 2nd page on your 1st page it will scan that
one too. Depending on the publicity of your pages this can take
several days to be scanned/updated. The more  your page is visited,
the more often googlebot will scan your page. When Googlebot finished
scanning it will again take some time until your page can be found at
google.com.

Dear Travis, 

Both sites are now indexed. BTW - it wouldn't be much help if you
linked the two - you have to be linked to other, quality, sites.