Init-tools
 

what are this init-tools needed to install the 2.6.x kernels? how do they work? How I have to install a 2.6.x kernel? What is the difference between installation of a 2.4.x and a 2.6.x?

module-init-tools

You need to download it to use 2.6 kernels.

Slackware-current package:
http://slackware.com/pb/?vers=slackw...ols-3.0-i486-1

It gives you a new version of modprobe, I believe, and other utilities the new kernel needs.

Difference between 2.4 and 2.6? Quite a lot. 2.6 is supposed to be about 10% faster during normal desktop use. You might experience new problems though.