Press release here:
http://app.lta.gov.sg/corp_press_content.asp?start=2068
3. The one-for-one card replacement exercise will end in September 2009, when the current EIFS fare system will be discontinued. After September 2009, the old ez-link cards cannot be used for travel on public transit. However, cardholders may still get a refund on any remaining value in their old cards up to 12 years from the date the card is first encoded for use.
I've got a decent amount of cash on my ez-link card, if I don't head to SIN before then, wonder how hard it will be to refund.