Well, this is a problem. And the problem is not just the dictionary, but the dictionary format.
The only open format I know is XDXF, see
http://xdxf.sourceforge.net/[
^]. This standard supports Unicode (of course, as it is XML-based); and one important point of using Unicode was support of transcription.
I've downloaded some dictionaries here
http://xdxf.revdanica.com/down/[
^] and created my dictionary application (very fast, indexing of the existing XDXF dictionary by converting it info internal format in disk). The dictionaries I currently use do not include transcription, but you can search around, may be you can find something. If not — you're out of luck. Well-known legacy standards like DICT are obsolete, so there is a little hope you can find transcription.
[EDIT]
For some more ideas, see my other solution:
Dictionary in android as app with eclipse[
^].
—SA