I have a string $tmp_string.

for ex., JIMMY-DIMMy

And I need to change the following:
first letter is in uppercase
other letters are in lowercase
first letters after "-" sign also is in uppercase

the result will be:
Jimmy-Dimmy

I know how to make Jimmy-dimmy, but how to make Jimmy-Dimmy...???

This will do what you're after.  If you want to do it in XSLT then I
you'll have to use a recursive solution in 1.0 or tokenize in 2.0 (or
1.0 + extensions) with translate and substring.

cheers
andrew