direct resolving IDN domainnames ?

This year many countries started handling non-standard domainnames
(containing german umlauts or swedish extraletters or whatever).

While I know (at least I think) how to deal with this new domainnames on
level of bind (using the ace-string / punycode), I dont know how to
deal with it on application-level.

for example on my server the domain "töst.at" would have a zone for
"xn--tst-sna.at" and I could easily ping "xn--tst-sna.at", but in some
future I would also like to ping "töst.at" any maybe my customers would
like to be able to resolve this domains even sooner.

So I'd like to know which libraries should be updated (if there are any
updates available yet), which applications (browsers, emailclients) are
able to handle this new domains and so on.
Maybe anyone has experience in this or maybe there is a good page on the
web ...
Or maybe I'm just asking to early

thnx,
peter