Recording in the classroom - Microphone?

[Pieter]

I've been tinkering with the idea to record my philosophy classes on audio. Allot of times I have so much homework to do that by the end of the day I'm just not in the mood to study anymore. So my idea was to record my teacher talking, so I can listen to it whenever I want.

Now I don't know if they would agree with wearing a microphone, they're very reasonable people.
But I'dd like to know if it would work well, and I'dd like to do it secretive because I don't know if there's legal matters holding them back.

I've got a 30gig MP3 player that can record to WAV and has a microphone plugin.
I just don't know WHICH KIND OF MIC to use.
It should be failry small, and able to record from a distance without having allot of garbage from around, altough classes are usually quiet.
I also shouldn't cost me an arm or a leg! It's just for recording speech.
Our school doesn't have an Aula, there are only about 250 students spread over 4 years.
And the classrooms are fairly small, something like the average highschool classroom I think.

[Snowman]

First thing I thought of was a nice condenser lapel microphone, that way you could conceal it and still pick up some good audio from someone speaking kind of far away. This is probably the one I recommend most for that exact use:

http://www.amazon.com/gp/product/B000815CF4/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B0007R6I9I&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=07W2870EWNF200FH4CQZ

Should be perfect for a teacher lecture, and it's very affordable.

[C.S. Murphy]

I don't think there's any problem with recording inside of a classroom considering that you're paying for the education. I see no difference in writing the information down in a notebook or recording it in a hand held device. The intention is the same...

  Snowman that is a great mic. I didn't see anything in the text that read that you need a power source for the mic which condensers need. It's a cheap solution.

  I personally use a Microtrack It has a t-bar stereo mic which is perfect for me and best of all.... It all fits in my pocket.

[Pieter]

Thank you both! I'm looking into it, if anyone else has recommendations, feel free!

[bluDi]

For cheap, state of the art quality (hehe), I trust dealextreme. See if these match your description or maybe find something else from the site. Shipping world-wide, no extra shipping costs.
http://www.dealextreme.com/details.dx/sku.4468
http://www.dealextreme.com/details.dx/sku.4466

Should be small too.