You need to recode the continuous variable (eg income) into a categorical variable. Examples:
You need to be careful with the categories with -recode-. If your second rule was (101/200) then an income of 100.5 wouldn't be recoded. The rules I've suggested work because once a match has been made, and the value recoded, it won't match any subsequent rules. See -help recode- and the Stata User's Guide.
-egen- requires less typing but the first number (in this case 0) needs to be less than or equal to the lower number in your dataset, and the last number (in this case 1000) needs to be greater than the highest income in your dataset - so you need to look at the data first. Of course you should already be doing that...
After you've recoded it's simply a matter of: