OPL2LPT is available as kit or presoldered board, here.
The soldering guide is available here
A video says more than a 1000 words... so ..
Here's a video by the 8 bit guy, it is a great introduction :
It shows how to solder the kit, and how to use the driver and patcher for games.
Here's a video review by Lazy Game Reviews :
Here's a video review by Phil's computerlab, using the OPL2LPT on a core i7 :