Do I need to play MGS:PO to understand MGS 4 ?

please no spoilers just a simple answer i have only completed MGS1 so far.

I do own a psp, wasnt planning on gettting PO but it seems there is a story.

DO you think after i finish MGS 2 and 3 i should pick up PO annd play it before MGS 4 comes out ?

I doubt you even need to play MGS3, just MGS2. However, I would definitely recommend the MGS Essential Collection, because MGS2 and 3 are two of the greatest games ever made (along with 1). Without spoiling anything, I will just tell you that MGS3 takes place before 1 and 2, and really just answers a lot of questions and offers insight to the events that happen in 1 and 2.

MGS4 takes place after MGS2. MGS: PO is a great game, and takes place 6 years after MGS3, but still long before MGS2. MGS: PO (and it's sequel) is probably the least necessary of the MGS games you need to play, not counting MG Acid. However, it is good, so if you can find it for a decent price, you may wanna play it anyway. I would definitely recommend 2 and 3 over PO though.

edit: err, I see you said you were gonna play MGS2 and 3, nevermind. ;) Enjoy, I'm sure you will.

MGS.PO is a sequal to MGS3 which is a prequel to the rest of the series. You don't have to play it to understand MGS4 but its a great game and worth playing, it does add to the storyline.

The actual storyline goes like this:

Metal Gear Solid 3 --> Metal Gear Solid Portable Ops --> Metal Gear --> Metal Gear 2: Solid Snake --> Metal Gear Solid 1 --> Metal Gear Solid 2 --> Metal Gear Solid 4

A little confusing lol