I just ordered some letters from santa for lydia and alex (and my little cousin, and my two step-nephews). They do one that is "baby's first letter from santa" so I thought I'd mention it in case any of you want to order any to put in your baby books. I thought they were pretty sweet http://www.santasfriend.co.uk/
Or do it for free - click here, click here or click here - these come via email or printed letter on screen (all personalised) which you can print off. Or you can post a letter in any Royal Mail postbox (I think it has to be by tomorrow or sometime in the next couple of days) to Father Christmas/Santa, Reindeerland, SAN TA1, making sure you include your child's name/s and return address so Santa can write back. You can also post it to Lapland, but then the reply apparently includes some marketing info from Lapland tourist board. Valentine Xxx