Over 100 parishes of Dorset have some coverage of baptisms and marriages on the IGI, which can be searched here:
http://www.familysearch.orgOther sites to check are:
Dorset OPC -
http://www.opcdorset.orgAlso FreeReg, found here:
http://www.freereg.org.ukOther transcriptions, which may vary in coverage of dates and types of records, are listed below.
With thanks to Aztec1 for posting the links originally.
Phillimore’s Marriages – online
Allington 1570-1837http://www.opcdorset.org/Allington_Bridport/Allington/AllingtonMarriages.htmAlton Pancras, 1674-1847http://www.opcdorset.org/AltonPancras/AltonPancrasMarrs.htmAskerswell, 1560-1835http://www.opcdorset.org/AskerwellFiles/AskerwellMarriages.htm Beaminster, 1837-1869http://www.opcdorset.org/BeaminsterFiles/BeaminsterMarrs1837-1869.htmBeaminster, 1761-1812http://www.opcdorset.org/BeaminsterFiles/BeaminsterMarrs1761-1812.htmBothenhampton, 1636-1812http://www.opcdorset.org/BothenhamptonFiles/BothenhamptonMarrs.htmBradpole 1695-1812http://www.opcdorset.org/BradpoleFiles/BradpoleMarriages.htmBroadwinsor 1563-1812http://www.opcdorset.org/BroadwinsorFiles/BroadwinsorMarriages1.htmBurstock 1563-1812http://www.opcdorset.org/BurstockFiles/BurstockMarriages.htmBurton Bradstock with Shipton Gorge 1614-1812http://www.opcdorset.org/BurtonBradstockFiles/BurtonBradstockMars1755-1837.htmCattistock 1558-1812http://www.opcdorset.org/CattistockFiles/CattistockMarriages.htmCerne Abbas, 1654 - 1812http://www.opcdorset.org/CerneAbbasFiles/CerneAbbasMars1793-1812.htmCharminster 1561-1812http://www.opcdorset.org/CharminsterFiles/CharminsterMarrsto1812.htmCharmouth 1654 - 1812http://www.opcdorset.org/CharmouthFiles/Charmouth.htmCheddington, 1756-1812http://www.opcdorset.org/ChedingtonFiles/ChedingtonMarriages.htmChickerell 1723-1812http://www.opcdorset.org/ChickerellFiles/ChickerellMarrs.htmChideok 1654-1812http://www.opcdorset.org/ChideockFiles/ChideockMarriages.htmChilfrome 1709-1866http://www.opcdorset.org/ChilfromeFiles/ChilfromeMarrs.htmCorscombe, 1595-1837http://www.opcdorset.org/CorscombeFiles/CorscombeMarriages.htmDorchester, Holy Trinity 1560-1812http://www.opcdorset.org/Dorchester/DorchesterHolyTrinityMarrs2.htmEast Chelborough 1690-1812http://www.opcdorset.org/EastChelboroughFiles/EastChelboroughMarrs.htmEast Stower 1584-1848http://www.opcdorset.org/StourFiles/EastStour/EastStourMarrs1813-1848.htmFleet 1664-1753http://www.opcdorset.org/FleetFiles/FleetMarriages.htm