How To Get Views Argument as a Like / Contains Instead of Equals
Solution would be to filter results by argument value. Unfortunately, this doesn't seem to be doable in Views at the moment. Not via the Views interface, anyway.

However, by altering exposed filter form to set current argument value as filter default value, users have managed to get such functionality to work: http://drupal.org/node/360780

I don't know what state it is in, but you may want to have a look at this module, which is supposed to do just that -- enable using argument placeholders (%1, %2) as filter values: http://drupal.org/sandbox/itangalo/1086472 (git only)