Oddly enough, we're talking about this in the Writer's Lounge. XD
For the first answer, twelve-point, Times New Roman. This is the default on my word processor and the standard for writing papers at my school anyway.
For the second, according to Writer's Market (the Bible for all aspiring writers), the standard is that you submit your transcripts in Times New Roman or another "professional" font (i.e., no italics or flowery fonts like Monotype Corsiva). The publisher can then decide how your book is best presented, but it's vital that you send it to them in a way that's easy to read for them and that shows that you're serious.