bottom bracket transfer langster to pompino

You need to consider two things when choosing a bottom bracket:
1) compatibility with your frame;
2) compatibility with your cranks.

The part of you frame into which the BB fits, is called the shell: the shell will be made to a particular standard.

The most common standard is ISO (International Standards Organisation). This is more commonly known as British or English.

Both the Langster and Pompino will have ISO/British/English shells, so a BB that fits one frame will fit the other.

Different cranks require different width BB for a specified chainline.

You're using the same cranks, so you don't need to change the width of the spindle.

http://sheldonbrown.com/cribsheet-bottombrackets.html