Potty Training Put Offs

I have been off and on again about the idea of potty training for a few months now.  The girls were interested and sitting on the potty frequently before the holidays but I put it off because I didn't think the holidays would help at all.  Now the holidays are past and I've been waiting for a good time to jump in.  I want to start on a Monday so we have a good solid week of being able to stay home and work on it before going anywhere (i.e. church and weekend activities).  I have a friend who has recommended the thick cotton training panties by Gerber.  She had difficulty training her girl so her daughter has grown out of some perfectly good training panties and this friend offered them to me.  But she doesn't come to visit until the 19th and I'm not even sure they'll fit  (2T and my girls really could use 18 month...skinny things).  Also we're going to start a music group with Early Intervention the following week (that is once a week and runs until the end of March) and I would love to give this a good shot before getting into that.  So  I'm putting it off again when I really don't want to.  I want to get on with it while the girls are still excited every time I mention "big girl panties" and "using the potty".

Any thoughts or tips on potty training?  Also would love tips on how to tackle potty training twins?  Thanks!