Hi Ricardo,
sorry for answering so late...
a)
MS Visio is a Softwaretool by Microsoft. You can create diagrams and much more with it. UML and so on. From the Structure you create in Visio, you can generate C++ Code. But I think it's not for C++ beginners. You have to know, what you do with Visio. So better learn from scratch.
A good point to start is at cplusplus.com
b) STL is the Standard Template Library, which holds many solutions for many problems. e.g. lists, maps, strings, sort, search, streams, ... Have a search with your favourite searchengine for STL and you'll find tons of information.
Boost is also a library for C++ extensions. They cover many topics like container, strings, io, memory, network, graphics ...
c) We use an eclipse-addon for development, which is designed for our processor and rtos.
There is a free gnu toolchain for eclipse, too. You'll find it in the forum.
d) We build our own framework
I hope you can go on a little further, although this is not very much information. But better you look at the sources for STL and Boost, than let me write about it. 
bye
Dirk
