Black applicants with respectable LSAT scores are rare, for two reasons: 1) the median LSAT score for blacks is 10 points lower than the overall median, and 2) there are relatively very few black test-takers every year. This leads to a huge imbalance (there are as few as 20-30 black males getting a 170+ on the LSAT each year) that continues to be true down in the 160 range where you are. This is a big part of why blacks are referred to as under-represented minorities
or URMs; there are so few of them even trying to apply to law school at all, let alone with the scores to get into top schools.
I'm giving you all this background because it is important for understanding your chances. Schools are allowed to give at least a "soft boost" to URMs by considering how admitting them will benefit diversity. They have to balance this against their current admission policies, which includes maintaining their LSAT and GPA medians for ranking purposes. Given that a key reason for low diversity enrollment is the shortage of high-LSAT applicants, schools seem more likely to forgive low LSAT scores than low GPAs.
You're in a different boat. SMU's median is 164, which means you're below both medians. This doesn't mean that they won't take you; a solid diversity statement and your work experience might provide the incentive for them to take you anyway. But you also have a great reason for a GPA addendum and can point to an upward trend as a reason you're more than your GPA. As a URM, they will consider the statements and addendums in your application a lot more strongly than other applicants. It's easy to see why, too. Looking at SMU's enrollment numbers, only 5% of their student body is black; you could help them boost diversity by attending, especially if you can give them reasons that you'd really want to attend SMU for your life goals.
The reason I said that is to make clear that your success rises and falls on your application far more than the standard applicant. You need to have a really good diversity statement and an addendum that very clearly delineates poor semesters from better ones. Whether or not they admit you will depend on the opinion they form of you based on how you present yourself. Make sure everything is typo-free and as well-written as possible. This is always important, but for you it's critical.
All that said, here are some people SMU has taken in previous years (all data pulled from http://smu.lawschoolnumbers.com/
2009: 164/2.51 (non-URM, had WE)
2009: 161/2.92 (non-URM, had WE)
2009: 167/2.56 (non-URM, had WE)
2008: 165/2.47 (non-URM, upward trend w/GPA addendum)
2007: 159/2.81 (non-URM, admitted PT; $24K scholarship)
Obviously SMU doesn't have a GPA floor, which is good news for you. Also, even for non-URMs, having WE and/or a GPA addendum appears to help. Hell, they've taken non-URMs below both medians with GPAs under 3.0 before. There's not much data on URMs with numbers as low as yours, but here's what I found:
2009: 151/3.23 (URM black male, military WE; went to W&L instead)
2008: 153/2.85 (waitlisted) (URM Hispanic male)
2007: 166/2.27 (URM Hispanic male; $45K scholarship)
2007: 169/2.75 (URM Hispanic male; $90K scholarship)
2006: 151/2.51 (URM black male, admitted PT)
2005: 163/2.31 (URM Hispanic male; admitted PT; $16K scholarship)
That's a wide spread of admits, but what I think it means is that you stand a good shot of acceptance there. (I don't think applying PT would help your chances, since USNWR recently started factoring PT admissions into the rankings, making schools treat them more like FT admits. However, it's worth noting their PT median last year was a mere 160.)
Houston should be much easier. You're already at their 161 LSAT median. They will probably throw money at you if they decide to admit you. Expect either a skeptical WL/rejection or an embracing $$$ offer from them.
I realize I'm throwing a wall of text at you, but I hope it is all helpful. Long story short, you have good odds at both of these schools, but I don't consider it a lock at either of them. I'd recommend choosing and applying to more schools in the lower T1 that you'd like to attend. It's possible many might reject you, but those that like you could possibly reward you with $$$.