Seeing as this is my daily business I feel qualified to add to the previous answer, you will not find such a cable as the two signals are not compatible (for many reasons; scan rate/resolution/sync signals/amplitude/polarity). SCART is designed to accept low line rate video (composite or RGB) signals, not higher res (VGA or better) PC signals.
If you have a newish flat screen TV (LCD or Plasma) it may already have a VGA or DVI connection. If it has HDMI then you can use a DVI-HDMI adaptor as they are essentially the same digital signal (HDMI = DVI + sound) but might need a separate sound connection.
If you have s-video out of your PC graphics card then you can use an s-video cable if your TV has s-video input. Don't try to use a s-video to SCART adaptor, they are only for the OUTPUT of devices which carry s-video signals via SCART as SCARThas no ability to accept s-video!! Be aware that the picture over s-video will be rubbish.
Keep it digital if you can (DVI/HDMI to DVI/HDMI).