Well you could just get a valueram and try overclocking it, you wont get great results though. I got my valueram 25 mhz overclocked without any problems, havnt tried going further.
Currently that Mushkin is on sale with a mail-in rebate for $199 at newegg. There is a review at www.xtremesystems.org that shows the Mushkin EASILY reaching DDR500 speeds, and many times going up to 260 MHz or 270 MHz. If I had to buy RAM right now, I would go with the Mushkin.