I'll start this out with a rather loaded question: solution to what??
Before I answer that, let's take a look at how a federal system might work in Iraq, and then we'll see if it meets any faction's idea of a "solution":
The fundamental problems in Iraq are several, but here are the big ones. 1) Oil and population are not evenly distributed, so tribes/ethnic groups living near oil want a larger allotment of the revenue, and tribes/ethnic groups not living near oil want that revenue shared equally. 2) Iraq is a fiction of British colonial cartographers--the lines in the sand do not reflect that many Iraqis look to Iran or Saudi Arabia for spiritual solidarity and leadership, nor that primary loyalties normally fall at the tribal-group level, not the state level. 3) There is a division through all levels and groups in Iraqi society between the desire for secular power (in a multitude of forms) and the desire for religious power (in a multitude of forms), which manifests in the various Islamic extremist groups and actions in Iraq.
Federalism was formalized in America to solve an internal division superficially similar to those facing Iraq: the founding fathers recognized that the US government must be set up to provide for effective central control and coordination, and appropriate influence by the more populous states and interests, while protecting the individuality and influence of the smaller, less populous states and local groups. For most parties, and for a while, this system worked fairly well, although there is no question in my mind that it collapsed completely long, long before I was born. The problem of adapting such a federal solution to Iraq is that, even in theory, federalism only works to overcome a single dichotomy (which is why it eventually failed in the US, which has multiple, if less distinct and divisive, poles of power). In Iraq, with multiple dichotomies, each with far more nuanced difficulties than faced a fledgling America, such a model simply will not work.
A Federal system will not solve the problem of distribution of oil revenues. Even if factions that want to profit from what they see as "their" oil will submit to a compromise of pooled revenue and distribution by population (or some similar scheme), the fact that there are competing an overlapping power structures that will want to receive this distribution invalidates this scheme. Tribes, religious groups, provincial governments, ethnic coups, etc. will all need to be cut in on the compromise. The difficulty of reaching compromise with such an interwoven and blurry set of interest groups is nearly impossible. It can, of course, be an "imposed compromise", but this will only result in those groups being imposed upon resorting (or continuing to resort to) violence.
Federalism will not resolve the problems created by British cartography, as it depends upon the drawing of lines in the sand, not the dissolution of the importance of these lines which, in Iraq, are one of the core sources of division. With interest groups, factions and loyalties overlapping into a muddy confusion, any attempt to make clean-cut divisions will fail--especially when the overlapping divisions are as powerful-yet-blurry as the distinction between secular government and Islamic government--a distinction that is especially powerful because of its cultural history in the region.
So, while it may be a cop-out from answering my original question of "solution to what?", I will simply answer no. Federalism is not the answer to the problems in Iraq, whatever they may be. There are more superficial reasons why federalism won't work being discussed on the news, such as the division of Kirkuk oil revenues, but in the end this is a a structural problem: Iraq is a landscape of highly multi-polar hierarchy, and any attempt to create a uni-polar hierarchy without removing the multi-polar nature of the region will fail.
Landscapes of multi-polar hierarchy are very challenging--simple models and solutions just do not function in the presence of such varied and lasting calcifications of history. While I think that localization and evolution towards a non-hierarchal, rhizome system is the best a"solution" to a world of highly multi-polar hierarchy, it is not a panacea, and will require time to wear down the old pathways of power. But the tendency of hierarchy to evolve unitary, if superficial structures will only fail in light of the memory and history of past (but asynchronous) hierarchies. It's like trying to build a house on the ruins of another house that has not been fully demolished, and repeating the process over and over again... any contractor will tell you that such a home will only be stable if you scrape away to the foundation and start over.