I would use a stanley 78 plane or a 289. But if you need to do just this one tongue (or tenon) the 78 would be cheaper. The 289 is a better tool in that its blade is skewed but they are pricy. A user #78 can be had on eBay for the price of a good quality router bit.
Pat Leach's site will give you the details http://www.supertool.com/StanleyBG/stan10.htm
You should be able to get 1"+ wide rabbet with a single fence setting. One on each side and viola, a tenon/tongue for your table top.
of course this requires that you know how to sharpen and set up a hand plane.
Hand tools rock. By the time most guys build their jigs etc, I am off to other parts of the project.
good luck
scot