Hey Joe, funny thing, i work at the IBM Olivos Site as well heheeh. you take subway line D until congreso. Then you take the bus 60. There´s several different routes, you need to take any 60 that has the word "panamericana" on the front sign. you tell the driver you are going to the San Lorenzo stop. The stop is actually on the panamericana, not on the san lorenzo bridge (which crosses the panamericana right through). You will see a whole bunch of geeky looking kids (i may be one of them eheh) carrying their laptops on backpacks or laptop bags. They´re all going to the olivos site. You dont have to go across the panamericana, the builduings (3 orange, due to the bricks eheh, buildings) are on the same side the stop is. you will see a petrobras gas station and right next the olivos buildings. the street separating the gas station from the buildings is called jose ingenieros, that´s not the entry, the entry is from repetto street, which crosses jose ingenieros. After you get off the stop, you walk up a little hill and then you´ll encounter street blas parera, the next parallel street to it is repetto.
on a side note, at the congresso subway station, on Cabildo avenue, as soon as you walk out of the station, there´s a small movie theatre, well, everyday at 35 mins passed 7, 8, 9, or 10 there´s an IBM bus/trolley what goes straight to the olivos site. So, before taking the bus 60, when you get off the subway station, see if there´s a long line of the same geeky looking kids, if there is, 90% chances they are ibm (there´s another company that has its trolley stop there, but there´s usually very little ppl for them)and are waiting for the bus. If you see the line, ask anybody if that´s the ibm bus, if yes, get it, no one will ask you anything and if they do no problem, you are working for ibm hehe. if there´s no line (and it´xtime passed 30) it means the trolley is gone already, then take the bus.
Anyway, hope you get to read this post before you leave home tomorrow morning.
Good luck to you on your first day at work and most likely i´ll see you there