Drupal - Views exposed filter to search multiple fields
Yes, you can have multiple fields search in a single exported filter using
Global: Populate filters and Views filter populate module.
Check this answer.
In Drupal 7, you can use
Global: Combine fields filter
to get the desired functionality. By using the same, you can select multiple fields on which you want to perform search.
I know this question has been answered already, but thought I'd chime in that there's another filter called "Search: Search terms" which basically emulates the Drupal node search and searches the whole node for the entered keywords. You can't select any fields to specifically search, and I'm not sure if it uses the "Search Index" view mode etc. But it works very well.
More info: http://drupal.org/node/680442