AVR-Chat

Something else to consider: How about Liberty BASIC? (www.libertybasic.com)

Very straight-forward, very clean and extremely low startup costs (free for 
personal/learning and only U$50 for full commercial version).

For some versions of Win, you may need to include a DLL (inout.dll) so that 
your program can directly manipulate HW if needed (like GWBASIC in & out 
commands), but I believe that this is in the public domain and is only about 
127 K bytes in size (41K zipped with C++ source) - www.daqchina.net look 
about midpage under DLLs and Software.