Hi Andrey,
The API with t/translation methods is far better, thanks 
Important thing is ability to localize currencies. Locales need to
convey informations about:
- number of digits after decimal separator (which the user can
overwrite if desired), - where to put currency sign,
for example:
currency:
format:
format: "%n %u"
unit: "PLN"
sign: "zł"
Some inspirations can be found here:
http://rubyforge.org/pipermail/railsi18n-discussion/2006-July/000065.html
Maybe I have an old version of R18n library, but it should let you
pass BigDecimal number to locale method. For some business apps you
cannot rely on Floats (because of rounding issues).
Kind regards,
Dawid