Developers can download from the links at the right the most recent version for the platform you are using. The source code programs you create or edit in one OS can be opened, worked on and compiled easiliy for the other OS with usually very little modification.
xBasic is self-documenting which is a very nice addition. With other languages, you as a programmer must explicitely write both code and documentation which in my experience seems to pose a big problem for most. xBasic comes with the ability to define pop-up hints attached to the objects as you create them, plus you can also define the help entries for the objects and then create a simple programname.hlp text file so that as the program runs both the developer and any subseqent user can at their leasure create their own notes. Think about the ease, as a developer, you right-click any object in a running program and presto! up pops the help center where you can document how to use the object. As a user you find the documentation too confusing so you simply right-click and add your own clarification.
Want an easy yet powerful drag and drop GUI designer, yep xBasic has it. Whats more, you can design your own GUI widgets and add them to as many projects as you like.