hi there :)
recently i have started to learn xml and xsl and i have some questions if you dont mind :) ...

1. xml:if elementes and predicates aren't the same thing?
2. xml+xsl are only to replace html + css?
3. in what fields do you apply xml+xsl? only in building templates ?(at least this is what ive seen by now :) google's blogger.com templates are built with xml and xsl ... but thats kinda all.. so here comes the 4th question:)
4. are xml and xsl going to be extincted or they're just at the begining?

1. they are not the same
2. nope as the browser still needs to read the html markup
3. xsl is mainly used as template form else there would be no real advantage of going to the trouble of setting it up
4. i believe xml and xsl are just at there birthing stages as xslt 2.0 released they will find yet more uses for it also noting that xml is pretty damn common on the desktop side of things aswell.