We bought tickets through http://www.idtgv.com/en/ and was able to buy with regular US credit card and print tickets at home. They don't have as many trains as regular site, but you can buy further out and get good prices. Be sure not to use USA as country of residence.

Goor info here: http://www.seat61.com/

Like DebitNM, in 2011 I bought two sets of tickets (Intercities Prem tickets from Paris St Lazare to Rouen and 2nd class reserved seat TGV tickets from St Pierre des Corps to CDG) online with a US credit card and printed them at home. I used info from the seat61 web site and it seemed fairly straight forward. I used this web site http://www.tgv-europe.com/en/ and randomly chose Macedonia as my country of origin so the web site would be in English. It was nice to have the tickets in advance and I think the fares were good too because I bought them as soon as they went on sale.

I see one of your reasons for wanting to buy tickets in advance is for reserved seating. Here is a short thread about our Intercities tickets that were not reserved seats. http://www.fodors.com/community/europe/have-prem-tickets-question-on-seating.cfm

Here are a few other sites I used. Hope you have a great trip!

http://www.gares-en-mouvement.com/en/

http://www.trainweb.org/tgvpages/formations.html

http://tgv.tgv-europe.com/second-class-tgv

I bought tickets from the SNCF website (french) and picked up our tickets at the train station. You can pick the tickets up in person from a person at a train station or a SNCF boutique. You don't have to worry about the pin/chip credit card. Bring a copy of your print out from SNCF.

I always just print them out at home. No need to go to a station window, no need to use a machine at the station, no need to composte the tickets. Just print out and take them with you (I make an extra copy just in case).

I was able to print my tickets Paris to Reims. I was not able to print my tickets Paris to Barcelona and those are the tickets that I had to pick up at the station.

Whether you can print at home or must retrieve in France has to do with the type of ticket. I have been been able to print France only tickets on my computer WHEN I could get hold of discounted non-refundable fixed-date tickets, while tickets for international trips came in two types: ones I can print and the others that require retrieval in France even for fixed dates.

I don't have chip and pin card, so I needed to see real persons in France to retrieve my ticket by presenting the same CC I used to purchase the tickets from home. This does NOT have to be done at the SNCF station. SNCF also has Boutique in town offices you can do the same at no additional cost. I try to avoid going to the SNCF ticket counter during rush hours. The line can be daunting. But if I happen to walk by SNCF ticket counter and see a short line, I would seize the opportunity to retrieve my tickets. I don't even do this Nice. There seems to be long lines all the time. Instead, I go to the Nice SNCF Boutique at the office opening time.

Originally, the print at home tickets were iDTGVs or PREMs. As these tickets are neither refundable nor transferable, the SNCF did not risk your using a ticket copy for travel and printing a second copy to submit for a refund. I have heard that the print at home option has been extended to other types of tickets, what is not clear is how the SNCF will prevent fraud when extending the print option to refundable tickets.

While picking up tickets at the kiosk is fast and easy, one always has the option to pickup them up at any service window or boutique. When picking up tickets in person, it should be stressed that you must present to the agent, for his inspection, the exact same credit card as was used in the original, on line transaction. The agent will compare your card numbers with those used for the original purchase. If your credit card is lost or stolen, meaning your new card has different numbers, there will not be a match and you will not receive your tickets. It is important to know that if you lose your card, you also lose your tickets.

The moment the flash code scanner has registered the use of a ticket, I imagine that the scanners will refuse any identical ticket.

I have been printing my own tickets for years, but the other day I was surprised not to be able to print the ticket I bought from Paris to Maubeuge. So I went and got it out of a machine. You cannot always predict if you'll be able to print the ticket yourself, but if you don't have a chip&PIN card, you just go to a ticket office to get it.

Thanks for the really helpful info folks.

I'll try to print at home (if it's possible.) I plan to buy a refundable or at least changeable ticket and I haven't gone far enough in the process (since my travel is in June) to see if a print at home option is available for those tickets. (Believe it or not, I've missed a TGV before.... by 2 minutes when traveling with the baby last time, so the ability to change plans at the last minute is essential for us.)

And if it turns out I need to get the tickets there, I'll just make sure I guard my credit card from now until June and track down an SNCF boutique station in Paris during the 9 days I'll be there.

Thanks again!

Even though others have done so, I forgot to answer your specific question. The tickets we printed at home were all we needed. We just showed them to the conductor on the train and they worked just fine. If you buy and print them as suggested above (and your trips are within France), you should be good to just get on the train with no need to go to a kiosk for anything. At least that was our experience in 2011.