The device that Imperion1 has suggested is certainly worth a try @ $8. The sound in an XPS is generally quite good so you will not likely need anything for that. The graphics in an XPS will support TV out on the digital stream; hopefully that applies to analog as well. The ideal situation now, would be to have a TV with HDMI which gives a much clearer image and manages the sound as well without additional hookups as are required with VGA and DVI.
Every XPS that I have seen has an S-Video port. Yours must be a newer, smaller unit like an M1330?