How can I send an email to a google contact group on my iOS devices? I have groups in my Google Contacts for sending emails to sets of people via the web interface on a browser.

I sync Google mail and contacts onto a couple iOS devices via Microsoft Exchange.

How can I send an email to a google group from iOS? Neither the built in mail/contact apps have any reference to my groups, and I cannot acces them via the web browser (mobile version), nor the official gmail app (which seems to be a resigned web interface).
Unfortunately, there's not a way of doing it with the native iOS app. Try using the Gmail app (which I personally prefer). If not, there's this little workaround: http://red66.com/2009/07/how-to-send-group-emails-from-your-iphone/

The gist of the workaround is to make one contact for the group and add a comma separated list of emails to the singular email field for the "group contact"

This doesn't allow you to leverage arbitrary groups and does require some manual setup, but once that's done you can email limited group sizes from iOS without needing a computer.