The Biblioteca Medicea Laurenziana is digitizing many of the manuscripts from its Plutei collection. Among those that have already been digitized and made available online is Plut.86.03, the most important manuscript of Iamblichus' work De Pythagorica secta (usually referred to in apparati critici as "F"). The manuscript includes: De vita pythagorica, Protrepticus, De communi mathematica scientia, and part of the Introduction to Arithmetic of Nicomachus of Geresa, and some other things. It dates from 1300-1400.
Doug and I have twice traveled to Florence in order to inspect the manuscript, with the assistance of the very helpful Laurenziana librarians and invigilators. We have also worked off of microfilm and printed out copies. But this high-resolution, color version (which can be enlarged) makes this work much easier. Check it out! (Thanks to Stephen Menn for the pointer.)
To the first folio of the whole manuscript:
To the first page of the Protrepticus:
To the eighteenth century catalogue entry:
To the English instructions for searching the whole database: