For the mostpart US tools run off 110v (and 50Hz too, as opposed to 60Hz, if I remember correctly). Basically, in most cases you will need a transformer to run US power tools here. I haven't tried it myself, but I have heard both good and bad things about doing this (the main problem that I saw one person refer to was that the tools can't achieve their full power rating on a transformer here - I don't know enough about electricity to judge whether that is likely though). Best thing would be to talk to an electrician or else have a chat with someone who uses 110v power tools - I have seen a few carpenters use them, for example, and as far as I know 110v is popular on building sites.
The DW625 is an excellent router, by the way. I have used one myself for a few years now. The US model might not be quite the same though. For example, the smaller brother of the DW625 is the DW621 and this model differs between Europe and the US - the biggest difference (and it is a whopper!) is that the US version of the DW621 can take 1/2" bits (and 1/4" bits) whereas the European version is limited to 1/4" bits only. I can't imagine the DW625 will differ so drastically between the US and Europe but there might be small differences. Incidentally, I believe the DW626 is the latest top of the range DeWalt router, and I presumed (perhaps incorrectly) it was going to take over from the DW625. You might either be better off getting a DW626 if the cost is about the same (don't know how much it costs offhand) or else look for deals where the DW625 is being sold off my shops who want to make space for the DW626.
If you want to buy 240v tools, the following sites are worth a look, but be sure to compare their prices with those available elsewhere before making a final decision as prices can vary a lot (there are a whole bunch of websites for European-based tool sellers out there, do a quick search in google.com and you'll get back a long list):www.axminster.co.uk
Remember to factor in delivery cost. Axminster give their delivery costs on their website, and I think the others do too. Also, remember that stuff coming in from the US is subject to VAT (21%) and import duty (in or around 7% I think) and all of that gets charged against your order cost plus your delivery cost - whether you get charged that is very much luck of the draw, but budget for it as it is no fun having a bill arrive unexpectedly with your order (speaking from personal experience here!). When you factor those extra costs in, plus delivery costs from the US (which can be expensive from some places), sometimes it is as cheap to buy either here in Ireland or from a European site.
I have used Axminster several times and can recommend them. I have used diytools.com only once and they were fine too. I haven't used Rutlands but they appear to have a similarly good reputation and some of their special offers are genuinely good value.