It exploded onto the software development scene 10 years ago and quickly grew to become a dominant force in programming for millions. But now, on its 10th anniversary, Microsoft's Visual Basic programming language is facing its biggest challenge yet. And unlike past threats from Borland Software's Delphi or Sun Microsystems's Java, the latest challenge comes from within Microsoft itself. While some programmers say Visual Basic.Net, the new iteration of the language, is a necessary change to keep up with the times and accelerate development, others call the language an "abomination" that is unnecessarily complex and different. Microsoft is expected to release 2 million copies of the second beta version of Visual Basic.Net at its Tech Ed conference in Atlanta starting Sunday. Winning support from its estimated 3.3 million Visual Basic developers is crucial to make its .Net software-as-a-service strategy a success. Developers say the changes in Visual Basic 4.0 pale in comparison to the ones on the table now. The first .Net beta release included more than 70 changes to the way VB has traditionally worked. In response to the complaints, Microsoft earlier this year pulled back a few of the major changes, including a change in the value of the constant true.