You can use the very useful dateutil package
from dateutil import parser
import pytz
UTC = pytz.timezone('UTC')
date = parser.parse("2013-08-23T15:23:03+05:30")
dateutc = date.astimezone(UTC)
print dateutc.isoformat()
# or user strptime to have in the format you want (without time zone)
print dateutc.strftime("%Y-%m-%dT%H:%M:%S")