The pop rock quartet, that swept away all the possible pop charts last year, with their intimate love song “Hey There Delilah,” from the band’s third effort All That We Need. Now Plain White T’s have announced that their hard at work writing songs for their upcoming, yet untitled, album and that they’ll soon hit the recording studios in spring. Here’s what the band’s frontman Tom Higgenson had to say about it: “Yeah, there’s actually…