Two quarterbacks who could potentially at least compete for a starting job somewhere, if their current teams either trade or release them, are Alex Smith and Matt Flynn. Both SF and Seattle respectively sound willing to trade if they get the right offer. Or possibly even cut Smith or Flynn if they can't get anything for them, simply because it doesn't make much financial sense to be paying someone starting QB money if they're firmly entrenched in the backup role. It seems like most of their potential trade partners are playing hard to get though, acting as if they're not that interested, in the hopes that the players will just be cut, and they can sign them without giving up any draft picks.
San Francisco isn't getting any traction on trading Smith because everyone with a functional brain knows that it's incredibly unlikely that they're going to pay his $1 million roster bonus in March, and that there's no way in hell he's going to be on the roster come April 1, when his 2013 salary becomes guaranteed.
I don't think Flynn's going anywhere, yet. Russell Wilson had a spectacular rookie season, far better than anyone could have expected, but the Seahawks can't put all their chips on him, yet. There's no guarantee he won't have a brutal sophomore slump. After next season, if Wilson rocks the house again, then yeah, I can see Flynn on the trade market.