Len i borrowed a book from a neighbour who's a real green thumb, it has an
interesting section about aphids which backs up a lot of what you said about
the ants-aphids relationship. here's a few snippets ...

"As they feed, aphids excude a sticky honeydew that attracts ants who feed
on it. Ants like honeydew so much that they take aphids hostage and make
them produce honeydew. Look for columns of ants marching around plants and
you will find aphids."
"This pest transports bacteria, fungi and viruses - more than any other
source. Destructive sooty mould also grows on honeydew."
"Any aphid control must also control ants if they are present."

"Most aphids have no wings, but those who do have wings about four times the
size of their bodies"
"Aphids give birth to mainly live female larvae, without mating and can pump
out 3-100 hungry larvae every day. Each female reproduces between 40 and 100
offspring that start reproducing soon after birth"

Control ...
"Manually remove small numbers. Spot spray small infestations. Control ants.
Introduce predators if problem is persistent."

Biological controls ...
"Lacewings (chrysoperla species) are the most effective available predators
for aphids. Release 1 to 20 lacewings per plant"
"Ladybugs also work well to exterminate aphids. Adults are easily obtained
at many retail nurseries during the summer months. Release about 50 ladybugs
per plant."
"Verticillium lecanni (fungus) available under the trade name of Vertalec is
very aphid specific and effective"
"Control ants by mixing borax hand soap or borax powder with powdered sugar.
Ants eat the sweet mix and the borax kills them. They excrete sweet borax
mix in the nest, which other ants eat and die."