[mack]

There is a small airport near Pattaya (U-Tapao) but as far as I know you will have to land in Bangkok and then get a taxi to Pattaya. A good time to go imo is during the Thai holiday of Loy Krathong, it's in November every year and is whenever the full moon is...in 2008 Loy Krathong is on November 24th. From the web here's a short blurb on it:

It's not a national holiday but an evening when Thais pay respect to the goddess of the waters by floating candlelit offerings on any and all waterways around the kingdom.

Many of the Thai women will dress up in fancy dresses and it's a great evening. Plus the weather is normally a few degrees cooler in November-December. But pretty much any time is good to visit, although I'd agree and avoid going during the week in April during Songkran unless you enjoy getting wet from people squirting or dumping water on you every day for a week.