We're happy to announce that Qt for Maemo 5 entered Beta status - this means that all APIs are feature complete and have been reviewed by multiple people. For us, this means that an intense phase of bug hunting and testing is starting. For you, it means that you can now finally develop without us changing class names or behavior all the time (*) :)
The current Maemo 5 SDK still contains gdb 6.8, which is unstable when debugging Qt applications. gdb 7 is scheduled for the next release, in the meantime, you can find a custom package at http://chaos.troll.no/~harald/gdb7/. gdb 7.0 is installed as "gdb7" (note the "7" suffix) to /usr/local/bin, so it won't clash with the existing gdb. Once gdb 7 support lands in the official SDK, you can safely uninstall our package.
How about QtDeclarative?
QtDeclarative is available for Maemo 5 ("fakeroot apt-get install libqt4-maemo5-declarative-dev"), but is still considered a technology preview.
How about Qt Creator or MADDE?
Unfortunately, neither full Qt Creator nor MADDE support is available for this Beta. Currently, the ScratchBox based SDK is the only supported development environment.
A big thank you goes to the Qt and KDE communities for all the patches, reports and discussions. A big hand also for Kevin Ottens for his Virtual Machine which accelerates Qt and KDE for Maemo development quite a bit.
(*) read/only QComboBox might change into a value picker button