Gaming Just got my PSP,a few questions

[lolzed]

well,just got it right now,my Mom's friend bought it,and I've read a few stuff about it,but I'm not sure since he didn't tell much...
1.How do you know if it's a 2000 or a 3000
2.The "Custom Firmware"plays ISO's and stuff right?then how am I playing games on my PSP without a UMD?does it mean I have the Custom Firmware in it already?
3.Explain the most common uses of the buttons:X,O,(triangle),(square).do these represent A,B,X,Y in NDS?if so which is which
4.on skinning,if you download a skin,is it like DS that there are many of them or do they come only in one .ptf file?
:-P I'm a total noob at this...

 

[War]

Please take a look at the PSP FAQs (Frequently Asked Questions) thread. Everything you asked can be answered by reading that thread.

 

[xist]

at question 3!