Now available on FindMyPast are browsable collections of Norfolk Archdeacons' and Bishop's Transcripts. These are also available on other sites.
As with all collections (and these are a great addition) keep in mind that not every parish sent records to the relevant archdeacon and/or bishop every time they should have done!
Use transcripts particularly to check up on illegible entries in the original parish registers (these are contemporary transcripts) or to find entries from now destroyed records, for example.
The searchrooms at Norfolk Record Office: The Archive Centre and Norfolk Heritage Centre have detailed lists of which transcripts exist for each Norfolk parish as well as microform access to them (in addition to digital access to various subscription sites). FindMyPast's press release suggests that 32 parishes (of a possible 700+) are in their Archdeacons' collection, amounting to more than 70,000 entries. There are more than 210,000 entires in their Bishop's collection, which tend to be of a later date.
Note: The Bishop covered the diocese of Norwich which included most of Norfolk and Suffolk, but there were two Archdeacons in the county - one for the Archdeaconry of Norfolk, and the other for the Archdeaconry of Norwich.