Welcome to the forums - first stop to check if a system supports esx is the HCL - https://www.vmware.com/pdf/vi35_systems_guide.pdf - to see if a system will support ESX but this does not necessary mean it will not - I did a quick scan and did not see it but perhaps someone else will step in if they have gotten it to work -

And yes the VI Client is how you manage your ESXi host -

No experience with the SC1430, but I've read that Scott Herold uses the Dell SC1435 in his lab:  http://www.vmguru.com/content/view/42/64/

Just got back from helping a customer install ESX 3.5 Update 2 on a Dell R200.  It's not on the HCL, but everytihng appeared to work well.  We got one VM running on it now, so I assume everything is good.  The customer is aware that he's on his own with this box if it melts down.

Hope that gives you some ideas for cheapo ESX servers for Dev/Test.  BTW, you manage ESXi 3.5 with VMware Infrastructure Client just like managing the full blown ESX 3.5 server. Good luck! 

-Sean Clark

http://vm.seanclark.us

I currently have esxi installed on a 1430.  It has worked flawlessly.

CPU's are dual E5335's @ 2ghz ea, 8gb RAM, PERC 5i controller.  I am currently running 3 64bit guests with this machine for a total of 8 guests in a production environment.  It runs anything I throw at it.

I have ESXi running on a single proc SC1430, the built in SATA controller was found on my system. I am running 64 bit OS's (my Exchange 2007 servers) with no issues.