I’ve published my stuff through http://www.lulu.com for paperback/ePub and Amazon Kindle Direct publishing (kdp.amazon.co.uk) for Kindle. Createspace is also worth a look but much more tied to Amazon
The downside is the revenue percentage they take BUT the marketing upside is worth it. Thoroughly recommend it for the first project..can I plug my book now?
If you want any help at all, please feel free to drop me a line. The withholding thing is not that hard to get through once you know how. Basically, you ring the USA IRS, ask for a EIN number then fill in a WBEN-8 (I may have those TLA’s slightly wrong).
Best of luck with it. Most important tip, grow a thick skin for reviews. I didn’t. Each bad one destroys a little bit more of me.