by now most things seem to be working mostly fine. summary of general points and unresolved nitpick items 
1. if some locales are not available, it would be nice to have the error message wrap - now it extends the screen a lot;
2. pofiles are currently stored in individual, language coded directories - supposedly, the other way is to have language name in the file name, which would result in less extra navigation when using, for example, pootle. so files would be all placed in the "po" directory and named like zabbix-uk.po etc (it's possible to split them by project, so maybe zabbix-frontend-uk.po and zabbix-server-uk.po, but maybe it's not needed because of reused strings... to be discussed)
3. it was suggested to use language code only w/o regional code for languages where it is not available, otherwise some tools might need manual linking of such languages, or some scripting around them. so uk_UA would be just uk etc (so with filenames it would be zabbix-uk.po, not zabbix-uk_UA.po)
4. when pofiles are generated later on, they should contain references to where the string is used - that most likely would have to be done by whichever tool generates the files;
(there should be a description somewhere on how pofiles are generated, and if it is done using nonstandard tools, these tools should be available in the svn)
5. mo files are binary ones that are generated from the pofiles - they should not reside in the repository. instead, there should be some easy way to generate them for users, and they should be auto-generated in all releases, snapshots and other builds - a makefile target perhaps ?
once these things are sorted out, this might be ready for the great merge 