Livan:
Download Motherboard Monitor. Its free and it shows temps of case, mobo and cpu along with core voltages and 3 sets of fan speeds and this works within Windows so you don't have to go into the bios to check temps.
Not sure what would be too high, but my guess would be 50C or below would be safe, although I think these cpu are rated for 70C. For normal applications, 50C would be plenty warm (its 122F). Ripping wave files takes cpu power, so if mine never got above 48C then I figure that's a safe temp.