This is for a site of a small real estate agency.
I have a
property_offer content type set up and offer type vocabulary, with 4 terms (Buying, Selling, Put out to lease and Take on lease). Then I have created a view with page display, for the front page of the site it lists all the offers, and there is also a page for each of the 4 terms.
How do I create an exposed filter for this view which must be available as a block so I can put it in a region of the site and it'll be available on all the other pages too?
Views support "Exposed form in block", see in views editing page. Set it to "Yes", and it will appear in blocks.
Have you tried "Exposed form in block: " in your views setting and set that to yes. This will make a block available in the block menu that has the filters in for that view. The png in this post shows you where. http://drupal.org/node/349099
There is a module called Better Exposed Filters which gives you greater control of views filters.
As mentioned by user348, Views > Advanced Options > Exposed Form in Block needs to be enabled. Note that first, Views > Advanced Options >
Use AJAX:Yes must be set WITH at least one Views > Filter Criteria as
(exposed) (check box for "Expose this filter to visitors, to allow them to change it").
Afterwards, go to
sitename.tld/admin/structure/blocks and place it in a theme region.