Regarding the problem of Aids and Bf, here are some thoughts I would like
to add in the discussion.
It seems to me that all the arguments that are put forward are rather
defensive. Just saying that the risk of dying from diarrhea is greater than
dying from aids, although true, is not completely satisfactory. There are
people behind statistics! If the facts of higher transmission of aids
through breasmilk is recognised, I think we should challenge the
researchers to find out where the risk lies instead of taking the lazy side
of saying: switch to formula.

In an article from the Lancet :

Ekpini ER, Wiktor SZ, Satten GA et al, Late postnatal transmission of HIV-1
in Abidjan, Cote d'Ivoire, 1997 Lancet 349:1054-9.

I read : "although 95% CI for the risk ratios were wide owing to the small
number of cases, late postnatal transmission was more common among children
with oral candidosis, and among children whose mothers had a history of
cracked nipples and  breast abcesses."
The authors , having studied the risk of late postnatal transmission
suggest weaning the children at 6 months directly to solid food and not
formula.
This might be a good idea or a bad one, I have no qualification to judge
but at least it goes beyond the alternative  breastmilk or formula.
On the other hand it is very interesting to find mentionned causes in which
we, as lactation consultants, can offer real expertise. For most poeple
around the world, cracked nipples are inevitable, we know otherwise.
It would be also important to raise again the issue of exclusive
breastfeeding as it is still very rare ( any other food or drink added in
the diet can damage the gut and could increase the risk).
Also why not ask other alternatives to breastfeeding or formula : donors'
milk, starting with a study in a developped country with good milk banks
where babies or HIV positive mothers would be offered human milk ( It can
come in lyophilysed form).or
heating the own mother's expressed milk ? 
All this controversy is very challenging for us who are so aware of the
uniqueness of breastmilk , but it could be an incentive not to react only 
in a defensive manner but to put forward our expertise to open new areas of
research to the scientists. 

Gisele Laviolle LLLI, IBCLC
France ( where breastfeeding is still suffering from the big scandal we had
in the  early 90's about HIV contaminated blood)