According to THR and, oh, everywhere, the future Captain America is amongst these actors; and since they are all apparently on a 30 day holding contract pending casting, it sounds pretty real:
Mike Vogel

Age: 30
Height: 5′ 10″
Pros: Pretty, in Cloverfield, in She’s Out of My League which looks pretty funny, turned down role of Angel in X-Men 3.
Cons: Pretty, in Cloverfield, short (well, same as me).
Michael Cassidy

Age: 26
Height” 6′
Pros: Was in Smallville and The O.C.. Tall.
Cons: Was crap in Smallville and The O.C.. Not blonde. A bit young.
Patrick Flueger

Age: 26
Height: 6′
Pros:Virtual unknown with no baggage in spite of being in The 4400, blonde, right height range.
Cons: Virtual unknown, a bit young, looks like a smug arse in this picture.
Scott Porter

Age: 30
Height: 6′
Pros: Awesome in Friday Night Lights (which is also awesome), was front runner for Superman in that botched JLA movie, looks the part, can sing and dance a bit.
Cons: Was front runner for Superman in that botched JLA movie.
Wilson Bethel

Age: 26
Height: 6′.
Pros: Virtual unknown, was in Generation Kill which is apparently pretty good, right height range.
Cons: Virtual unknown, bit skinny, scary eyebrows.
Chace Crawford

Age: 24
Height: 6′
Pros: Pretty, is in Gossip Girl, which isn’t exactly a pro, but worked for Blake Lively on the superhero front and was all I could think of.
Cons: Pretty, too young, is in Gossip Girl, is Chace Crawford.
John Krasinski

Age: 30
Height: 6′3″
Pros: Plenty tall, could bulk up, can act, has fanbase.
Cons: Has huge amounts of preconceptions and baggage, may be too comedic a draw, will break internet in half and lead to even more ‘Steve Carrell as Red Skull, Rainn Wilson as Baron Von Strucker’ jokes than we’ve had in the past day.
Apparently in the running but with scheduling conflicts:
Garrett Hedlund

Age: 25
Height: 6′ 1.5″
Pros: Plenty tall, virtual unknown with no baggage, is in Tron Legacy.
Cons: Looks a bit weedy, virtual unknown, bad hair.
Jensen Ackles

Age: 31
Height:6′1″
Pros: Pretty, right height, can act, was in Smallville and, of course, is Dean Goddamn Winchester and really that should be enough.
Cons: If by ’scheduling’ issues they mean, ‘is shooting Supernatural season six’ then that’s a pretty big problem. Otherwise, not a one.
Of the listed contenders, I know who I’d prefer (Ackles or, failing that, Porter) but is this a real list, or is it just a smokescreen to cover for someone inexplicably not on the latest list, but was mentioned earlier:
Ryan McPartlin

Age: 34
Height: 6′3″
Pros: Is Awesome in Chuck, literally.
Cons: May be too Awesome.