The recording part is simple. Adapters which will let you connect to a regular tape recorder, and complete tape/digital recorders with integral telephone interface are widely available, for example:
Maplin Electronics -- Telephone recording devicesAs for the conferencing section, we could use some more details. Are the four lines you want to conference together direct exchange lines, or are they all extensions from the university's PBX? If the latter, then you might already have some conferencing facilities available on the PBX with some simple programming.
If direct lines, do you actually need to set up all four calls from the same location to start the conference? If it's acceptable for party #1 to call party #2, then #2 calls #3, and #3 calls #4, you can do it without any extra hardware by just using 3-way calling from each phone in turn.
Otherwise you have two major routes to take: Either use a third-party system where you call into your control number, then set up the four calls (or you can have each of your callers dial into the system if you wish), or set up your own conference bridge between the lines.