I'll be the first to admit that I don't pay much attention to the West teams, so I don't really know what the Blue Jackets need at the moment... though they have one of the lowest Goals For in the league, so they may be looking for a forward capable of putting points on the board. Though they also have one of the higher Goals Against, so who knows really...
The number one trade bait people have been talking about on the Pens is Tyler Kennedy. Maybe he is stifled by being stuck on the 3rd line, maybe Staal was carrying him, or maybe he is just having an off year. Whatever the reasoning, he has been under-performing this season. However, he has shown the ability to shine offensively in the past, so maybe on a team in search of offensive production he could make a crack at the Top 6. He also was a staple of the PK in past seasons, and as part of the Check line is not overly terrible defensively. He could be just what the Blue Jackets need.
Another possibility would be Dustin Jeffrey. I would hate to lose Jeffrey, despite the fact that he got very few opportunities to prove himself in past years playing mostly limited minutes on the 4th line, and more often than not just being a healthy scratch. However, in the past he had been a point per game scorer, before blowing out his knee he looked like he could contribute at the NHL level. He has been trying to get back in the lineup since then, but the Pens are pretty stacked up front., but he was able to prove during the lockout that he is still capable of putting up a decent amount of points (granted, it was in Austria). He isn't a tough grinder like one would normally expect on the 4th line like he usually gets stuck playing, and despite the fact that he normally plays Center, he isn't that good at faceoffs. However, he is good on the wing, and in a system in search of a Top 6 scoring forward he could be a better option than Kennedy, and also brings in a bit of defensive ability, and has played both PP and PK (so has Kennedy).
They could also be shopping around a D. The Pens are currently carrying 8 D on the NHL roster, so they're scratching 2 a night (though at the moment one is injured Martin). Despres and Bortuzzo are the obvious choices, being that they are the young D that keep getting scratched. Despres is the less reliable of the two, his is mostly offensive, and at times forgets he is bigger than most of the people on the ice, so one game he will use his body and the next he won't. He also has a bit of an issue with turnovers... but when he is on his game, he is amazing, easily Top-4 D. But in the Pens, he is the 7th or 8th on the depth chart. Bortuzzo is the opposite, he is reliably defensive, but his scoring is few and far between. He has a history of being an excellent shut down D, and while he doesn't have wuite the size of Despres, he seems to throw his around more. Another possibility would be Orpik, since there seem to be quite a few people who are unhappy with his play of late. He is pure defense, and was one of the best in the league in recent years. He may be having an off year, he may be getting old, or he may be better than the stats indicate. If the Blue Jackets are looking for D, we've got plenty.
As for who the Blue Jackets have that is worth the Penguins trading for? That would be something I need you to tell me. I know the have R.J. Umberger, and while it would be nice to see him come home, we don't need another Center (although some places list him as LW) and Columbus isn't going to part with their best player. Cam Atkinson seems to have decent scoring stats, he could benefit the Pens, they still never did find a permanent left wing for the 2nd line. Vaclav Prospal would also be a possible rental player, he's getting older, but is still a decent winger. Plus there is Artem Anisimov, but he is another C, so unless he is able to shift to wing they wouldn't really need him. They could also be looking for prospects, I don't know who the Springfield Falcons have, but they are one of the best teams in the AHL (tied for 1st, but with 2 fewer games, 3rd highest goals for, and only Baby Pens have better goals against), and the rate Columbus is going they will have some high draft picks.