Depends -
Are you asking if there is anyway of increasing the storage capability of a 2Gb card so that it can hold say 3Gb of stuff - then No there isn't.
It's like if you have a 2Gallon jug - you can't stick 3 gallons in it
If you are asking is there any way of making more space on a 2Gb card then it depends on what you have already stored on the card, & what you are going to use it for.
You could 'zip' files to make more space, the only problem is that whatever you use it on may not be able to 'look inside' the zip file. for e.g. if you got a load of mp3 stored on it - you could 'zip' them, but if you place it into a mp3 player then it will only play the mp3 that are NOT in the zip file (not that you'll get much more space trying to zip a mp3 file - 'cos mp3 are already 'compressed')