Jainism is, along with Buddhism, one of the two new "religions"
that offer a different path from the mainstream Brahmanism which
follows the Caste system (pre-determined social/spiritual status at
birth).
You can read about the relationship between Buddhism and Jainism
here:
http://www.urbandharma.org/udnl2/nl041304.html
In the past, Buddha used to engage in Great Debates with the Jains.
Buddha does praise Mahavira, although there are different views,
e.g on issues about Karma.
Upali, one of the Jain masters, converted into Buddhism.
Upali was one of the chief
followers of the Jain master, Mahavira. Because of his
intelligence, Upali often appeared in public debates on behalf of
the Jains.
There was one incident where Upali had a debate with the Buddha. At
the end of the debate, Upali was so impressed with the Buddha's
teachings that he asked to be the Enlightened One's follower.
"Venerable Sir, please allow me to be your follower".
To that, the Buddha answered, "Upali, you are at the height of your
emotions. Go home and reconsider it carefully before you ask me
again".
Upali was extremely impressed, "If it was any other guru, he will
parade a banner saying, 'Mahavira's chief lay-disciple has become
my follower'. But you, Venerable Sir, you asked me to go home and
reconsider. Now, I want to be your follower even more. I will not
stand up until you accept me".
Finally, the Buddha agreed to accept Upali, under one condition,
"Upali, as a Jain, you have always given alms to Jain monks. When
you become my follower, you will CONTINUE to give alms to Jain
monks. This is my condition".
Upali agreed to this condition. He later became one of the Buddha's
chief disciples. Upali was known to be the one who compiled the
Vinaya, the rules for monks.
