If you need to transliterate Cyrillic to Latin alphabet or vice versa the best solution is:
This site is doing miracles - words are useless here, just go and check it out.
The following site is not a tool for automatic transliteration but it can provide the official (i.e. used by the government) transliteration of a Bulgarian personal name, a name of a city etc. :
Greek is a bit more difficult story.
For Greek to "Greeklish", go to http://www.translatum.gr/converter/greeklish-converter.htm.
For "Greeklish" to Greek, go to http://speech.ilsp.gr/greeklish/greeklishdemo.asp. This is a demo but if you really need it, the software is at a reasonable price.