If you copy or substantially quote parts under this license then your source code must have that license too. If you distribute binaries that are based on this software then the license must somehow be in that binary (read, it is good enough that if you dump all text strings of a binary, the license in whole is there too).
There is no further restrictions, if you only link against a lib and you don't provide the lib or the lib is the original from the maintainer (you still may have compiled it yourself though) you don't have to do anything else.
Also be aware that license stuff is hugely country depending, what is illegal in the US might not be in Europe. For example Microsoft's standard EULA is not up-holdable in court when under the Dutch jurisdiction.
If you are still unsure, look at how Apple uses BSD software in MacOS X or how Microsoft used the BSD IP stack in their Windows 2000 family OS. If even that is not good, before you spend money on a lawyer, contact the _original_author_ of the software, explain your situation in short and ask if that is OK with him/her/them.
Think of the BSD/MIT license as you can do with it whatever you want as long as you don't claim authority on the code. This means you are not allowed to copy the code, remove the license and sue the original author for copyright infringement. It is usually also explained that if you use the code and the result is some disaster, nobody should say that the original author is responsible for that disaster.