Question in regards it to a cold wallet, moneroaddress.
When depositing coins to your cold wallet, you can check to see if you received them. You just have to enter the view key, public address, and tx id on xmr.llcoins.
Now, how can I check if there have been any transactions since you've initially deposited them? Verifying that there hasn't been a hack on your wallet>
There is currently no easy way to do this. However, in the future there might:
https://www.reddit.com/r/Monero/comments/51i0n7/solved_it_hopefully_heres_how_we_can_make_the/What would be the best currently available (though not easy) way to do this?
First, you'd have to fully sync the blockchain on an online computer. Second, copy simplewallet, bitmonerod, and the blockchain to an USB and plug that into the offline computer. Third, use bitmonerod in offline modus (--offline flag) and it should use the blockchain you have already synced on the online computer. Fourth, use --restore-deterministic-wallet to create a wallet with your seed offline. Lastly, use refresh to sync your wallet. It will refresh up to the last block you have synced online. It should then show all the transactions (both incoming and outgoing) of your offline wallet up to that block.
That's quite an ordeal. I think someone (moneromooo?) was working on a way of getting the key image from a transaction so you can check the spent status using Moneroblocks API... (like Luigi's coin checker)