Hi,
Its also worth checking out the Ireland Offline website for topical conversations on this very matter.
However we run the Eircom Istream solution in our office.
The price is reasonable, we had basic problems with our first _cheap_ modem as it kept dropping connections every time someone in the office coughed but once we got this replaced (the modem, not the dude that was coughing :) ) it has worked out quite well.
We do get the odd connection drop however but its bearable.
–g