Funny you should ask, I was looking into this today.
VMware shares outstanding is 382M, the IPO floated 33M, and EMC retains 329M shares (along with 98% of the voting rights).
The "stub" of EMC, that is, the old school data storage company minus its stake in VMware, is worth $12.3B at today's closing prices. That is 10.27 times its trailing earnings (ex-VMware) of 1194M, and 1.10 times its trailing revenue (ex-VMware) of 11.2B. That's the same core business that was rewarded with P/E in the mid 20s in 2004.
For comparison, VMware in its entirety is valued at $38.9B, which is 310 times its trailing earnings of 125M, and 40 times its trailing revenue of 974M.
If you think EMC's core business is worth more than 10 times trailing earnings, you can buy EMC and sell VMW, like I did at today's close. It might be a rough ride but if you've got the liquidity, it's very difficult to lose in the long run. The theoretical hedge ratio is 6.37 shares of EMC for every share of VMware.
Incidentally, that means that should VMW reaches 6.37 times EMC's stock price, then EMC's core business will be valued by the market at zero dollars. Seems implausible but it could happen. Remember 3Com's spinoff of Palm? There was a while there when 3Com ex PALM had a significantly negative market value.
Martin