As for the second question, I use coinbase. As to the first, never try to time these things. You will be beaten by people with more information. Instead just slowly trickle in and have pre-defined rules about when you will sell rather than trying to time an exit. Though I admit I broke my own advice and did an impulse-buy the other night when everyone was panicking over Gox and the price was $100 less than a day before and a day after.