GPS working perfectly!!

You should be able to get GPS without even having a SIM card. I've always operated in Standalone mode with Hot start. Perhaps Justin is in "Network Provider" mode?

I use GPS test from market. All it does it tell you what satellites are being used by your GPS and how strong the signal is. If you don't use your GPS often, try clearing the GPS data (or don't use hot start) I also use SGS Tools just for the secret codes because I'm not good at entering them.

If you don't have a SIM card in a GSM phone it doesn't connect to a GSM tower (unless you are on CMDA in which case the SIM is built in). You must have at least a dead one installed to make emergency calls. Try it.

I have GPS not "GPS". Because I am running in standalone mode it doesn't matter where I am, my GPS finds my lat and long. I get a better fix if I don't use wireless and never show up next to cell tower. In Canada there are lots of places with marginal cell coverage; my GPS works better than the cell phone coverage. As I suggested check your GPS settings. Your provider may have defaulted your to a crippled mode.

@Justin - In Canada if you are on the GMS network with Bell, you cannot make a call without a SIM card. When my SIM card broke, I had no call ability. There was no way for the tower to check that I'm supposed to be on it so it didn't even see my phone. Perhaps in the US it is different. For your problem, you should be on one of the US SGS forums, not this one.

If your GPS still fails, like mine, consider this :
http://www.addictivetips.com/mobile/fix-samsung-captivate-gps-issue-get-position-faster/
(Must read!!!)

My changed configuration looks like this :

SUPL/CP Settings
=============
However, I selected Server FQDN Type= AUTO Config.
I don't think supl.google.com port 7276  or  www.spirent-lcs.com  7275  (found on a lot of forums) will work for everyone.
Sure did not for me...
When you select to have the server Autoconfigured, it will select the server available.
I got (Belgium) :
Server:
h-slp.mnc001.mmc206.pub.3gppnetw
Server Port: 7276
(but both are on a yellow background: they are automatically configured. No user input required !)
Make sure, however, to select
SUPL Secure Socket= ON  (default = OFF, if I remember well)
AGPS Mode=SUPL

APPLICATION SETTINGS:
===================
Session type=Tracking
Test Mode = S/W Test
Operation Mode = Standalone
Start Mode= Hot start
GPS Plus= ON
Dynamic accuracy= ON
Accuracy= 50
GPS Logging= OFF

Oh, yes, I did NOT have to change, prior to modifying this in LbsTestMode,
Settings > Location and security : Use wireless networks : ON->OFF.  Just leave it ON. No problem.
After these changes, you DO need to power off, and back on your Galaxy S, in order for the changes to be implemented.

My system : GT-I9000
Firmware version : 2.2
Baseband version : I9000BUJP5
Kernel version : 2.6.32.9
Build number : FROYO.BUJP7