there a lot of "IF" there.... what kind of cluster is your desired, how is your enviroment to support a cluster, what license of IDS you have...
Read the manual... check the IIUG presentations... watch the webcasts, read the e-book of Carlton Doe about IDS 11.10 (if you are using the version 11.10 or 11.50), read the articles on the IBM site...
First learn the kinds of cluster, what you can and can't do with each one...
Choose the type of cluster where better fix in your environment , check if you have the apropriete licenses for they use, check if will be need to change your client applications and finally go to implementation...