The B110: Socket 478, intel 865GV chipset, supports 800 fsb, integrated intel "extreme" graphics II, of course no agp. Decent for an office machine or video encoder.
About the PSU, have you read
this thread? The 250 watt unit is no slouch. It will perform well for what he will start out with (2.53 GHz Celeron D, mATX mobo). As long as the guy doesn't use too much graphics card he will be fine with his new mobo (it seems that the OP is only looking to get a board with AGP/PCIe, not do a platform change to dual core or anything of that nature). As I mentioned in my last post, if the power supply does become a problem, all he has to do is replace it an aftermarket power supply, as the Dell unit uses the standard dimensions of a power supply. Do you know of a decent image hosting site, so that I can post pics of how the Dell PSU in this case is exactly the same dimensions of any other standard power supply? A new Thermaltake unit would slip in there just fine.
You are correct about the 12v rail: 14 amps.
Not good enough for cutting edge, but its fine for socket 478 and Celeron D. It was even fine enough for higher-end Dells that use hyperthreading prescotts at 2.8 GHz, DVD burners, and 512 mb of ram. The OP made mention in another post about switching to Northwood P4. That would actually lower the power consumption of the cpu, freeing up more watts for a graphics card.
Honestly the biggest hurdle will be figuring out the front panel wiring. It's not nearly as bad as Dell used to make it (you should see how crazy my Dell 4500 is), but it is something to consider. That and to figure out how he wants to cool it. An 80-90 mm exhaust fan along with standard intel hsf will work fine; it just won't be as quiet as it used to be.
If the OP wants the EASIEST route, all he has to do is find a motherboard out of a Dell Dimension 4600 on ebay (cheapest), or purchased through Dell (very expensive). It has AGP, is socket 478, and will literally fit right in and hook right up to his B110, no modifications required. It will even be more of an upgrade, as I sports 4 ram slot instead of two, has dual channel support, and has 2 SATA hookups.
Here is a link to one on Ebay right now. The price is cheap enough too! It doesn't say the seller will ship to Hawaii, but perhaps the OP can sweet talk him into it.
What's even cooler about going this route is that your Dell OEM Windows XP CD will treat this like a regular Dell, and install wiindows without ever making you go thorugh product activation. Who knows, it might just be similar enough that you won't even have to reinstall windows XP at all, it may just update itself for the SATA controller, and whatever audio chip it's using (of course drivers will probably need to be downloaded from Dell's support site, not too hard at least).
To top it all off, the 4600 uses the exact same 250 watt power supply as used in the B110. I'm sure that will make everyone happy in this thread.
The standard cooling solution for the Dell is more than adequate for the original configuration.
I still don't think that spreading FUD is the best approach to a topic like this.