According to the newest episode of PULSE, the US PlayStation Store will begin updating on Tuesdays starting May 4th. This is not long after it was announced that the EU PlayStation Store updates would be moving to Wednesdays.
 
EDIT: Adding embedded video starting at relevant portion
 

thank god 

Beat you to it.... by 30 seconds  
 
http://www.giantbomb.com/forums/general-discussion/30/psn-updates-moving-to-tuesdays-fuck-yeah/405701/#1

" Beat you to it.... by 30 seconds  
 
http://www.giantbomb.com/forums/general-discussion/30/psn-updates-moving-to-tuesdays-fuck-yeah/405701/#1 "

Someone posted this a week or two ago, still pretty cool even though this won't matter much since your still waiting the same amount of time for the update.

" @Gabriel said:

" Beat you to it.... by 30 seconds  
 
http://www.giantbomb.com/forums/general-discussion/30/psn-updates-moving-to-tuesdays-fuck-yeah/405701/#1 "

But his avatar is cooler.   And since this one all ready has more posts..... "

Huh, I guess all update news will happen on Tuesday... When was the Wii's updates again?

"
@The_Laughing_Man said:

" @Gabriel said:

" Beat you to it.... by 30 seconds  
 
http://www.giantbomb.com/forums/general-discussion/30/psn-updates-moving-to-tuesdays-fuck-yeah/405701/#1 "

But his avatar is cooler.   And since this one all ready has more posts..... "

That's subjective.... and I don't care Mods can lock mine if they want.     "

What was the reason for the change? And why are people excited about it? It's just a change in schedule, you'll still be getting the same things.

Thank the lord! My friend was bitching about it updating on thursday and likes that 360 updates earlier in the week, this will make him a happy person with this news.

And so Microsoft will move to monday, then sony to sunday, and all the way till we are back where we started

" And so Microsoft will move to monday, then sony to sunday, and all the way till we are back where we started "

good to know I guess, not that I care much it's just a change in schedule 

That is good news. no more of that xbox has automatic two day exclusivity crap.

And now xbox updates will be moving to monday nights.

Tuesdays are a better day for me. Gives me time to enjoy a game. I go out on weekends.

" And so Microsoft will move to monday, then sony to sunday, and all the way till we are back where we started "

MMmmmm so update changes tomorrow... can't wait

Yeah, Im down with tue updates for sure.  Much better to get stuff early in the week.   =)

" Someone posted this a week or two ago, still pretty cool even though this won't matter much since your still waiting the same amount of time for the update. "