I have read that lactic acid yeast is good for resoring ph in the gi tract to encourage good bacterial growth and to help the probiotics you take colonize because lactobacilus can't if the ph isn't right. What is lactic acid yeast and where can I get some?

There is more detailed information on these here:

http://curezone.org/forums/fm.asp?i=1676236#i

Both Saccharomyces boulardii and Saccharomyces cerevisiae are lactic acid yeasts.  You should be able to find these in most health food stores.