I own a Cobalt raq 4i, from rackshack
512 mb ram
Some decently popular websites are on it, about 25 domains, only 5 of which recieve heavy traffic.

I have an average of 280-350 processes running at a given time, all but 40 of which are httpd.

My RAQ is CRAWLING since the server move at rackshack on Saturday. I do not know if this a bandwidth problem on their end, or the big traffic increase in my sites.

My RAQ is crashing occasionally from too many httpd processes eating it's memory. That I can deal with, and have been able to do a fair job of controlling. The newest problem though is after my server has been running for an hour or so, it flashes the error:
sh: fork: Resource temporarily unavailable
To any command I type in. I cannot do anything via root telnet until I reboot using the control panel.

Any advice?

Get a better operating system?

Seriously, your options are 1. edit Apache's configuration to stop it spawing so many processes, or 2. recompile the kernel so that it will survive the load.

Of course, neither of these is going to help for long -- the real problem is that you've got too much traffic for your raq to handle. If I were you I'd move up to a better system (preferably with FreeBSD, of course).

How would I go about doing either of those?

A RaQ3 or RaQ4 should handle 1.000.000 or more hits a day if you use static websites. But if you use CGI- or PHP-scripts or MySQL this might be the problem. Hint: Look for chat-scripts on your server.

If you use scripts on your high-traffic-domains try to reduce the complexity of those scripts or try to substitue these scripts with static html-pages.

Daniel