I play both mandolin and tenor banjo. While the positions for the fretting hand are fairly similar (assuming both are tuned EADG ... scales will be different for a tenor banjo tuned CGDA and taking into account some of the comments about fingering Geoff the Duck has mentioned relating to the wider stretch), picking hand techniques will be somewhat different, e.g. the playing of triplets. Some of this is easier to pick up by listening and watching rather than reading in a book (I've heard that the Sully book is OK but haven't read it myself).

There are a couple of useful websites such as this one and this one that you may find useful.

Zen