my boyfriend has said that he wants to try pegging, which am quite turned on about but what am needing advice about is the best strap on to get? am thinking he has just made valentines so much easier :)
I've never used a strap-on before so hopefully other member's who have will share their opinions. But I'd suggest having a look at something like this http://www.lovehoney.co.uk/product.cfm?p=809 I know it's pricey, but Tantus products are extremely high quality and completely body safe so it will be well worth it.
we had looked at that one and this one http://www.lovehoney.co.uk/product.cfm?p=13499 as we have only ever used this toy http://www.annsummers.com/p/landing-lights-vibrator/07anavas1020041 which is just rubbish, and all my vibs/dildos are on the large side for him,
not had the chance to try pegging, but there's been a lot of posts on the forum on it and there's plenty of experts out there who'll likely be on later with specific adivice. In the meantime check out this blog post as a starting point -
http://www.lovehoney.co.uk/blog/2010/01/04/pegging-the-easy-guide-to-anal-sex-for-men/
i saw that and gave it a good read 
Me and my wife use the red rider harness, the harness has a o ring to hold the dildo in place so you can change the dildo to smaller or larger, the dildo that comes with it is very good but not for someone whos not experience, I`d start with something smaller. But i`d def start with a harness with a o ring, one that is comfortable with yourself, then choose a dildo he is comfortable with, start small you can always go bigger, good luck and enjoy yourselfs.
Have a look at the http://www.lovehoney.co.uk/community/forums/sex-tips-and-talk/321957-pegging-male-pride-confidence-boosting/ which iss a boosting thread on pegging which may help and give you some hints and tips too.
Also check out the strap ons that LH has to offer http://www.lovehoney.co.uk/sex-toys/strap-ons/
We have looked at the strap ons but were wanting to hear what people that use them thought were the best for beginners
Reading some reviews may help you too
Would suggest the starter strap ons in the L H catalogue and then progress to something larger as I have now it won't take to long but go steady and use lots of good anal lube and the lots more remember take it slow and talk to each other as you start more lube don't rush hopefully your getting the idea and don't forget more liube EJOY yourselves it feels great you won't regret it I'm sure
I would definately get a vac u loc harness because you can pick and choose which attachments you like the look of , all the attachments are of a high quality also , not been into it very long but the vac u loc stuff is superb if I had to recommend, xloads of attachments to choose from ,