ugrading drupal

hi ,
being new to drupal i wanted to update drupal 5 contributed modules to drupal6. i upgraded my drupal core modules to drupal 6 using the convetional ways posted in the site..but i am finding it difficult to upgrade some contributed modules to drupal 6 as they have became obsolute. so i am confused what to do... plz suggest me what all measures i have to take to upgrade those modules to drupal 6.plz help me out from this situation...

thanks in advance,
Vilash.