From version 2.5.0.11, Darts for Windows 2008 has full support for sound files to announce the scores. Record your own files or use the one from a certain pc game named PxC World Championship Darts or something.... To get the sound files, buy the full version from here. A free demo version is also available. Search Google for the demo by clicking here. When you have installed the PxC World Championship Darts, go to the folder where you installed the game and open the folders "\Resources\Sounds\Announcer".
Open another copy of the file explorer and browse to your installation path for Darts for Windows 2008. Open the folder "\dfwsound". Copy the following files from the "\Announcer" folder to "\dfwsound" folder:

• The files Player1.wav,Player2.wav and gsm.wav
• All files starting with an_
• All files starting with gl_
• All files starting with gls_
• All files starting with yr_

To enable the sound in Darts for Windows, go to the menu "Settings" and click the item "Options".

Tick the option "Enable sound".

The sound effects can be turned on or off at any time during a match by right clicking the background in the main screen (as shown in the picture below).

From version 2.5.0.20, it is now possible to assign a WAV file to a players name. You must first of course record your own sound files for the names you are assigning the soundfile(s) to. Place the recorded sound files(s) in the same folder as the other sound, then click the menu "Tools > Add new players" and assign the filename to the players of your choice (see picture below).
DO NOT ADD THE .WAV EXTENSION TO THE FILENAME, ONLY THE FILENAME ITSELF

Tip: It is only support for up to 35 legs if you use the sound from the pc game. Beyond that, DfW expects a file called gameshot.wav. If you know how to use a wav editor, open one of the gl_ files and create a new file called gameshot.wav by copying only the part of the gl_ file saying "Game Shot" or record your own "Game shot" file.