They are split up by county, the same as on FMP (where they have been available for years). Links below.
As with any new databases on there, you may find you get error messages and need to keep refreshing to get them to come up for a day or two.
Anglesey Parish Registers
Brecknockshire Parish Registers (aka Breconshire)
Caernarvonshire Parish Registers
Cardiganshire Parish Registers
Carmarthenshire Parish Registers
Denbighshire Parish Registers
Flintshire Parish Registers
Glamorgan Parish Registers
Merionethshire Parish Registers
Monmouthshire Parish Registers
Montgomeryshire Parish Registers
Pembrokeshire Parish Registers
Radnorshire Parish Registers
Unlike the English PR's, the post-1754 marriages and post-1813 baptisms and burials don't seem to be separated out into their own databases.