apache and php ate up all my memory :-[

Hi all Probably some Apache/mysql/php-Admin gurus can give me a hint : i just moved a website to it's own server ( my first one). now apache had eaten up all physical and virtual memory some httpd had allocated 45MB of RAM, memory ran out myqsl crashed... php is compiled in to apache Apache/1.3.19 (Unix) PHP/4.0.4pl1 these are the relevant entries is my httpd.conf Timeout 300 KeepAlive On MaxKeepAliveRequests 500 KeepAliveTimeout 15 MinSpareServers 5 MaxSpareServers 20 StartServers 20 MaxClients 150 MaxRequestsPerChild 500 in the php.ini memory_limit = 8M ( but i think that has nothing to do with it) i can't find anything in the logfiles exept that some httpd were already killed by itself, because there was no memory left that they could eat.... needless to say that my site does NOT get that much traffic that the server was at the edge of it's capacity..... HELP... Sebastian