A Dynamic Ip is usually issued to a computer under the DHCP protocol (Dynamic Host Computer Protocol) that doesn't already have a static Ip.
you can find your Ip and its relevance by doing the following:
1: In Vista click the windows Icon/ In Xp press the windows button on keyboard
2: In the search colum type 'command prompt' - this will start a new BLACK oblong box where it will enter DOS (disk operating system) command sequence.
3: Once at this point type in: ipconfig - this will fetch all the details concerned with your Ip (internet protocol) address.
Hey presto you now know which Ip you have (dynamic or static)
Hope that helps you.