Hi Christopher,
Maybe I shouldn't respond (since I'm not Catholic), but here's how I understand justification by faith and works.
Usually, it's easy for a protestant to think that 'justification by faith and works' sounds like it contradicts Eph 2:8. But that's just the problem: Eph 2:8 mentions being saved by grace, not by works. But this 'works' is referring to works of the law. If you read Romans you can find clear parallels with this verse (I just don't remember exactly what verse).
In anycase, there's 2 types of works:
1) Works of the law
2) Works of righteousness
In Eph 2:8, Paul was referring to works of the law, since the law brings death (Rom 8:2).
Now, we know that salvation is a gift graciously given by God. Thus, we don't do anything to earn salvation. However, once a believer is given new life, he/she must walk with our Lord. In other words, believers walk to maintain salvation. That's why scripture says "work out your salvation with fear and trembling" (Phil 2:12), because salvation is a process:
1) We are saved (Eph 2:8)
2) We are being saved (1 Cor 1:18)
3) We will be saved (Mark 13:13)
That would explain why Jesus tells us that those who are his sheep WILL abide in him and follow him, but if the believer doesn't continually remain in Christ, then he/she will be cut off (check out John 15:1-6). The Christian life is no joke (Luke 9:23).
So for the Christian, grace has been given to believe in God and also to do the good works. It's up to the Christian to remain in Christ (again, check out John 15:1-6).
Basically, I think the 2nd half of Gal 5:6 sums up the 'confusion' between James theology and Paul's theology:
"The only thing that counts is faith expressing itself through love. " (Gal 5:6)
Hope this helped =)
God bless!
-Jason
P.S. It's interesting to know that some Reformed brethren say that justification is by faith alone....but some define 'faith' to refer to an active, living, risk-taking, God fearing faith =)