Susan,
I have personal and professional experience with tongue tied infants who are
able to bf without frenotomy (clipping).  First let me state that some infants
are totally unable to bf without it, others are able, especially if mom has
really elastic breasts.
        Things that seem to help:  Using the football hold, and bringing the
baby more upright, so he is almost sitting on mom's hip, this allows the
tongue to fall forward a bit.  Nursing on one breast until the infant is done,
even if this takes an hour.  Almost always, a tongue tied baby needs to nurse
much longer than one with a free tongue.  Modeling tongue extrusion (having
the family stick out their tongues when the baby is watching, so he will
imitate, encouraging the baby to try his best to extend the tongue as much as
possible).  Experimenting with a slight amount of head flexion (not neck
felxion which can stress breathing by pushing the larynx upward) to allow the
tongue to contact the breast differntly.  Getting the baby's mouth open widely
seems to be very important.  I do not beleive in pushing on the chin, except
in rare instances.  The rooting reflex (triggered by having mom brush her
nipple very gently on the center of the lower lip) includes opening the mouth
widely.  The mom will have to be patient and try repeatedly as the baby learns
to open wider.  If she waits to bring baby toward the breast until he is wide
open he will learn.  If can be challenging for a tonguetied infant to open the
mouth widely while sucking, as tongue and jaw movements are linked, but baby
can improve at this as well.  Many moms have told me that getting baby to open
wider was most helpful.
Hope these can help the baby you are working with.
Catherine Watson Genna, IBCLC