Chabad have an article on what the ketubah says.
The focal point of the document is the financial compensation due to
the wife in the event of the marriage's dissolution through divorce or
widowhood. The ketubah even includes provisions which place liens on
the husband's different assets.
When a Jewish man marries a Jewish woman he automatically obligates
himself to his wife in ten areas; some are Torah mandated and others
by rabbinic decree. A number of these obligations are mentioned
specifically in the ketubah and others are implied: He must 1) feed
his wife; 2) clothe her; and 3) provide her conjugal needs. His estate
is obligated to 4) pay her a lump sum in the event that he divorces
her or dies before she does. He must 5) pay her medical bills if she
falls ill; and 6) ransom her if she is taken hostage. If the wife
passes away before the husband, he must 7) pay her burial expenses,
and 8) after he dies, her children inherit their mother's ketubah
money before the rest of the estate is divided amongst all the heirs.
In the event that the husband dies before the wife, 9) she is entitled
to live in his home and live off his estate until she dies or
remarries, and 10) her daughters, too, are supported by his estate
until they marry.
Today, the standard ketubah is a printed form which has blanks for the
date and the names of the bride, groom, and witnesses.
The Wikipedia article references a “text of a prenuptial agreement” = ketubah at http://www.rabbis.org/ endorsed by the Rabbinical Council of America. (There is a link on the right hand side of the page under “Commonly Used Forms”).
Chabad have a text too – follow the link.