I just released version 0.2 of the Haskell text library that I announced back in February. This version fixes a number of bugs, but much more significantly, it adds a streaming mode: you can process a huge amount of text lazily using a small, fixed amount of memory, while maintaining high performance.
In case you need to report problems or suggest improvements, there’s now a Trac instance for the text and text-icu libraries.
As always, you can easily download the source:
darcs get http://code.haskell.org/text/