Matt and Kev are both completely right, but one thing to remember is that if you are not using Enterprise edition you may need to use the NoExpand query hint to take full advantage of the view. More detail on this is available at http://www.sqlservercentral.com/articles/Indexed+Views/63963/ which is something I wrote a while ago when we started using indexed views.
Depending on your exact needs, you may also be able to add calculated columns to your table and put indexes on the calculated column.