Hi,
On Geofabrik I found the new pbf-files. They ar much smaller, so I would
like to use them. Are there any ready-to-use files of osmosis, splitter and
mkgmap which can use the binary format?

For the splitter and mkgmam, support is in a branch in the subversion repo. For osmosis, it is in trunk. You'll also need to pull out my git repo that contains the common code and build that (Or, you can snarf the jar out of osmosis trunk.)

Which new parameters I have to use for osmosis and splitter?

For osmosis, see my announcement of a release candidate for the options to use. Note that --write-bin and --read-bin are being replaced by --write-pbf --read-pbf.

Scott