Yes, you can create your own module that:

1. Adds an on_change attribute to the field in the view
2. Creates a method that gets called by the on_change attribute in #1. The method returns False if the date chosen is greater than today.

For example, in your form view you would have:

<field name="my_date" on_change="onchange_date(my_date)"/>

Then in your object you would put:

from datetime import datetime
from openerp.tools import DEFAULT_SERVER_DATE_FORMAT

def onchange_date(self, cr, uid, ids, my_date, context=None):
    if datetime.strptime(my_date, DEFAULT_SERVER_DATE_FORMAT).date() > datetime.now().date():
        return False
    return my_date

Edit: add example of constraint mentioned by Priyesh:

A constraint has the added benefit that it doesn't depend on the client interface calling the on_change method. It always gets checked when a value is written to the field.

def _check_date(self, cr, uid, ids, context=None):
    obj = self.browse(cr, uid, ids[0], context=context)
    if datetime.strptime(obj.my_date, DEFAULT_SERVER_DATE_FORMAT).date() > datetime.now().date():
        return False
    return True

_constraints = [(_check_date, 'Date is in the future!', [my_date])]