I have never performed it, but you have pretty much 2 options.
Take your Peachtree information and export it to excel, and then import that
to MS Accounting (you will have to change some things, go to the help menu in
Office Accounting and then click Microsoft Office Accounting help and click
on the search tab and type in peachtree.)
There is also a company that will assist you in your migration, there site
is http://www.dpdynamics.com/ I have never worked with them, so I cannot
really comment on them but it might be something you want to look into.