[Knitty's list of standard abbreviations can be found here]

Body
Using circular needle, CO 144[160,180,200,216] sts. Place marker and join to begin working in the round, being careful not to twist.
Rnd 1: [K2, p2] to end. This rnd forms 2x2 rib.
Cont in 2x2 rib until work measures 13 [14,15,16,17] inches.
Place next 12 [14,16,18,20] sts on waste yarn, work across 60[66, 74, 82, 88] sts, place next 12 [14,16,18,20] sts on waste yarn, work to end of rnd. Set aside. Do not break yarn.

Sleeve (make 2)
With dpns, CO 52 [60, 68, 76, 82] sts. Place marker and join to begin working in the round, being careful not to twist.
Work in 2x2 rib until work measures 2.5[3, 3.5, 4, 4.5] inches. Place next 12[14,16,18,20] sts on waste yarn. Place all rem sts on spare dpns, break yarn, leaving a long tail. Set aside.

Join Sleeves to Body
NOTE: Read through this entire step before beginning.
Using circular needle and ball of yarn attached to body, and working in 2x2 rib as set, work across 40[46, 52, 58, 64] sts of one sleeve, work across 60[66, 74, 82, 88] sts of front of body, work across 40[46, 52, 58, 64] sts of second sleeve, work across 60[66, 74, 82, 88] sts of back of body.
There should now be 200[224, 252, 280, 304] sts on the circular needle, and the sleeves and body should be joined, ready for the yoke to be worked. At the underarms, the sts on waste yarn from the body and from the sleeves will be opposite each other. These sts will be joined later on.

Yoke
If desired, switch to a longer circular needle at this point.
Cont in rib patt as set until work measures 5[6, 7, 8, 9] inches from joining point.
Sizes S, M, XL, and XXL only: Next Row: [YO, k2tog, YO, k2tog, k2, p2] around.
Size L only: Next Round: K2, [YO, k2tog, YO, k2tog, p2, k2] to last 2 sts, p2.
All sizes: Work in 2x2 rib for 5 more rows. BO all sts in patt.