What can be said about the soundtrack itself? One half of it is a throwback to good old times when Yukes composed scores to each game it developed and a must-have for fans of Smackdown soundtracks (especially WWF Smackdown! Shut your mouth). Another one contains wrestlers themes (most of them are shared with Allstar pro wrestling and King of Colosseum so use your opportunity to grab these because Allstar pro wrestling series are a lot harder to rip than Wrestle kingdom and King of Colosseum games), you can call them "Japanese stuff".
And the last thing – you shouldn`t worry about lack of the first game because the second game contains most of tracks from it.
Wrestle kingdom 1 & 2 streams* (http://anonym.to?http://mediafire.com/?u993lo335ho7r)
* – the only thing of possible concern is that I substituted an actual opening audio track from WK2 with its WK1 counterpart. They aren`t actually "counterparts" at all as the musical theme featured in openings of both games is the same however in WK2 it`s slightly longer but only because of roughly 5 secs of audience cheering put into the very beginning of the respective track.
All I can say about the music itself is quite short and simple: if you have ever been digging any of 5 WWF / WWE SmackDown! original soundtracks then checking the 2nd game`s rip (or better both as not 100% of the 1st title music was transferred to its sequel) is a must. It applies to anything not tagged with prefix "bgm_d0" (those are entrance themes which are pretty diverse in style and sometimes they even enter grounds belonging to J-Rock / J-Pop / dance / traditional Japanese and all kinds of easy listening genres) at least (however the ones only interested in spiritual successors of SD fighting themes can also throw away most "bgm0"-prefixed tracks as well). I personally absolutely love WK2 compositions with names starting with either "game" and "menu" words as they sound as close to SD4 (IE "Shut your mouth", my most favorite of all 5 iterations) as they get.
Update: I`ve also stuck kind of "light" version into this pile of awesomesauce on a huge Yuke`s plate of offerings. It`s light not only in terms of size but also in regards to difficulty of playing the tracks back as all the tracks contained in the newest pack come from X360 ver. of the game which appeared to be even easier to rip than I expected having remembered my experience with versions of UFC 2009 & WWE LoWM on the same platform.
And most recent mirrors all courtesy of Knurek of HCS64 team: I for PS2 (http://psf2.joshw.info/w/Wrestle%20Kingdom%20(2006-07-20)(Yuke%27s).7z) & X360 (http://x360.joshw.info/w/Wrestle%20Kingdom%20(2005-12-22)(Yuke%27s).7z) and II for PS2 (http://psf2.joshw.info/w/Wrestle%20Kingdom%202%20-%20Pro%20Wrestling%20Sekai%20Taisen%20(2007-05-10)(Yuke%27s).7z) (all single archive styled ones).
Cheers!