We cannot answer that question as we dont know what megapixel your camera is.
If your camera is 2 mega pixel a 2Gb card will hold about 2,000 pictures.
If your camera is 6 mega pixel a 2Gb card will hold about 600 pictures.
If it is larger than 6 mega pixel then it will hold less than 600 pictures.
You can also set most cameras to take pictures at "high quality", "medium quality" or "low quality". Obvioulsly the higher the quality setting the less pictures your memory card will hold.
Here is a chart that may help.
http://www.lexar.com/support/faqs_gen.html#8