Shame Oxfordshire don't do a county wide M.I.'s CD like the BMSGH do for Worcestershire with a county wide index. I find it a very useful tool and well worth the money covering more than 175 graveyards and burial sites.
http://www.ofhs.org.uk/CDsales.html#mis gives the list of photographically illustrated MI CDs, plus the MON07 CD with over 150 graveyards on (mostly with plans), and with a full index.
And if you don't want to pay for the full CD, by using the Search Services you can have a search done in the burial index database for a small charge.