With Poco you need to do some compiling, yes.
Poco and Boost address different levels of programming. Boost gives you the kind
of general functionality that conceivably could be directly part of the standard
library, intended to help you build more directly practically useful
functionality. Poco is meant to give you the more directly practically useful
functionality, more like Java's standard library, at the cost of having more
dependencies between parts so that it's more of an "all or nothing" thing.
That said, I don't see what this has to do with Windows programming. Both
libraries are general, portable C++ libraries. You should have posted in a C++
group such as [comp.lang.c++], and I've cross-posted this reply there.
Cheers & hth.,
- Alf