The first thing every sound fed into your sound card is converted to is a WAV file (german thinking sounds funny in english, eh?). So - yes it is possible to do that conversion by software. It is what will be done without further effort.
BUT-T--TT---TTT! Sound cards are built into PCs and PCs are designed to cope with digital data not with analog sound. That means you can often hear the data being processed in that sound you record - clicking of your hard drive, noise form - yes - the sheer bits hurrying through your computer. Let me tell you: Electromagnetic interference that can not cause a transition from zero to 5 volts within some nanoseconds is not considered critical inside of a computer. But when it comes to analog recording we have to talk about millivolts and milliseconds.
So if you want some real quality I would indeed recommend to consider recording with a DAT recorder first. They also incorporate digital electronics but much more care is taken to keep its noise away from the analog part than is within a computer. At least I hope so.
And I also hope that helps a little.