This module extends the Webform module and allows you to display different confirmation messages depending on the values entered. You can set up multiple conditionals and the first conditional rule that matches the values entered will be used. For example it's possible to say if
field A is X display one confirmation message, but if
field A is Y display a different message.
However, it's currently only possible to check the submitted value for one field for each configured message, i.e. it's not possible to say if
field A is X AND field B is Y, show this message. If you need this functionality, then perhaps try the Rules module combined with Webform Rules and the PHP filter. It gives you more flexibility setting up the conditionals but you have less control over the confirmation message.