Hi Milan,
You can download the EMML Reference implementation from the OMA website and use it to learn and try the EMML language to develop your mashups.
http://www.openmashup.org/download/
If you are looking for commercial tools such as a mashup editor/mashup server, you can try downloading the Presto Enterprise Mashup platform product from our Mashup Developer community at:
http://www.jackbe.com/dev
You don't need Presto to learn and try EMML. That is what the EMML Reference Implementation at OMA is intended for.
hope this helps,
thanks!
-deepak