...and I am looking for software to help me. It is not exactly diagramming sentences because words seldom need to be written at an angle. Any suggestions?

If you're looking to do Reed-Kellogg sentence diagrams, you probably want this tool:
http://www.sendraw.ucf.edu/

If you're looking for x-bar or graph-based sentence diagrams, I'd probably encourage you to try one of the linguistics packages for LaTeX. Certainly if you're doing this for a thesis or something it's worth the learning curve; you'll save time in the end. One such package is LingTrees:
http://tug.ctan.org/tex-archive/macros/latex/contrib/LingTrees/lingtrees.doc.pdf