First, let me say I agree with Dirk, this is not something that we would expect, or anyone else should expect from geeklog/apache.
Having said that, before we can do you any good please let us know a little more about the environment that this is set up in. What OS you're running, what version of apache, what version of php, if php is a module or cgi, etc.
It'd be even more helpful to us, if you have access to the machine (and I'm hoping since you have top or ps you do), if you can configure apache to use server-info and tell us what processes are taking the most time for apache.
It'd also help for you to explain what you mean by "working on the site", what exactly you're using and doing. If memory starts going up that normally means, in my world, that there's a memory leak. If you're always viewing your pages with an older version of mozilla or netscape for instance on linux, that could be the source of your memory leak. Even depending on what you're using to monitor your system (GTop, ROX system monitor) could be leaking (though I'm not accusing them).
If you are using a system monitor you might cut in the important sections to a comment so we can see more details.
I know I haven't solved anything yet, but hopefully you'll give us the tools to help you. The last thing we want from geeklog is to find out that when certain planets align (and i'm in vegas on vacation) we just start chewing resources.