Don't worry, the projects easy. Use serial addressed thermometers, better still the DAllas DS1615 units which have dataloggers on chip and a simple rs232 interface,

Use a DS2250 for a controller, whih you can program through its serial port, Use a simple 2 line 16 character LCD, code on this site for the display.

Email me and I can sell you an EasyPC PCB that will do most of what you need (25 quid ?) I can supply you with all the bits as a kit if you need them, because Dallas stuff can be tricky to get in small quantities.

Let me know if you want it.

Steve