In case you are not aware, Monday-Wednesday many universities hold these sessions with free booze and food, and the faculty (including those on the search committee) typically stay in their room, while everyone else is floating around from one to the other. While this is a joy-full experience to the hungry students and to the hand-shaking professors, for you this now almost a PUA-type of job...
Try to hit as many of these sessions as you can, starting with the hiring universities, obviously. Note: alcohol help to loosen your tongue, so maybe start with some that are not as important to your search and load up on beer :) When you enter the room, do your best to identify the important people (ie, the ones on the hiring committee). These tend to be the older folks, and typically, they will have a crowd of desperate job-seekers, such as yourself around them. Go and approach these professors, and *ahem*
Usually, start with extending your hand, introducing yourself and then just start pouring your research into their ears. Think of it as an "elevator-pitch", where you have just 5 mins to impress an investor (because, eventually, someone else will butt-in and steal your spotlight). Make sure that your name-tag is visible, and have your resume on hand, plus some business cards. Ask them for their card, and find out who else from their department is around that you could talk to. Maybe even ask if they would hand you off to the next professor.
For conversation topics and questions you should be asking, see my post about the interview:
Unless, you were approached a department representative at the poster session, this is a low yield activity, but you have to try... if you were indeed approached and invited, then treat this as an effective mini-interview. Try to talk to EVERYONE from the department.
Also, some schools will flat out offer to interview you at the conference (some "teaching" departments did that to me). Obviously agree to do that, go meet them up for coffee or whatever and have a chat. Not as good as an on-site interview, but better than nothing.
Also, also, make sure to invite people to your talks, both when you meet them and when you submit your packet to them online BEFORE the conference. You can indicate the date and time of your talks in the cover letter, and if they are interested, they may come... And also FOLLOW UP with the people that you've spoken to, after the conference, in order to indicate your enthusiasm for the position.
Finally, if you see me anywhere, feel free to ask me to introduce you to whomever is your target... I'll do my best to try, lol.