Could you advise a site to learn Texas Hold'em, interactively?
The best interactivity is playing with other real opponents. Just open a poker client and keep playing. If you are to scared to play for real money play for play money. After you finish your session do a hand review. Pick a couple of hands which you remember as tough or pick the ones where you won most or lost most and see what you did to get to this outcome. If you are puzzled then ask someone to give you a comment. Trial and error is the best way to get better.
I don't know exactly what you mean by interactive learning. The best way to learn is to read the basic theory and then practice and practice. If you're very very new to the game, playing micro-stakes online is a good starting step. After you do that for a while, call a few friends and play a few hours at your house (or at their house). Or go to a local casino and play some small buy-in games.
Read the rules and then head off to your favorite (or soon to be favorite) site that lets you play for play money. Once you feel ready for real money, transition over. The sites available vary by geography, so you'll need to poke around to find the ones accessible to you.
Personally I read the rules, watched WPT and WSOP, and played a lot on Poker Stars as well as some home games I knew about.
If you are asking for a place to learn strategy, I would agree with those above. The best way to learn the game is to read some beginner books and play. If you are not a big reader I would suggest Daniel Negreanu's book "Hold'Em Wisdom for All Players" because it is such an easy read and gives strategy withot beingg too technical.
If you want an interactive app, I know that there is an app called WPT Poker Trainer, so maybe give that a go!
There is actually a WSOP Texas Hold Em app in which you can play offline mode. Your opponents are AI and play in a variety of typical styles. This uses 'fake' currency so is a great way to learn the dynamics of the game without investing real money or playing with people who play silly online with fake currency.