Both Scrum and Kanban are really process "skeletons". Neither is specific to software development. Scrum was popularised by software development organisations but is positioned as general management technique rather than a software project management technique. Kanban emerged from manufacturing and has been adapted to software development, initially by maintenance teams. Both Scrum and Kanban aim to manage the flow of units of work through the team that is doing that work, measure how fast work flows so that estimates can be made more and more accurately, and make bottlenecks highly visible so that they can be addressed.
Because neither is specific to software development, teams using Scrum and Kanban add software development practices to the process to help them incrementally and iteratively release and improve the software. Most teams, whether working within a Scrum or Kanban process, adopt the technical practices of XP and reflective practices of Crystal.
XP is basically Scrum applied to a single team plus guidelines about what makes code "high quality" and how programmers can achieve that. Crystal Clear also applies to small co-located teams but is more flexible about programming practices although it also recommends the XP practices (the book describing the process is excellent and full of invaluable advice, whatever process you decide to go with). Scrum teams also usually adopt the reflective practices of Crystal: regular "heart-beat" retrospectives and larger retrospectives after every major milestone. Kanban requires continual reflection and improvement but some teams use retrospectives too.
If you want to start applying an incremental/iterative process in a small programming team, then I think XP is a good process to start with because it sets the bar pretty high for technical capability and is very well documented. How continuous-flow and Kanban best applies to different areas of the software development industry is still being debated on the kanban-dev mailing list and elsewhere.
I would recommend also performing regular retrospectives to improve the process and adapt it to your specific situation.