Yes, Vegas can do this.

As for other solutions, it boils down to "how much money to you want to spend?".

Nearly frame rate conversion is going to have some flaws; the better the process, the less you'll see.

Vegas can do this, in various ways, with good results. Probably the easiest is to use the "interpolate" style deinterlacing, and then just render. Internally, Vegas will effectively convert 60i to 60p, toss every sixth field, forming 50p, which it will render out to 50i. Reverse this and change "toss" to "duplicate" for PAL to NTSC conversions.

External equipment can do it, also with variable results, depending on what you spend. The super high-end stuff has motion estimation so it can "synthesize" frames that didn't previously exist.

You can also send it out of house (for example, to Sonic Foundry Media Services) where they will use a combination of software and high end hardware to convert it.

Sometimes, if you know the contents of the source tape, you can modify the conversion to work better. For example, if you have an NTSC source that is really telecined Film, do an inverse telecine on it, and render to 24p (see the "film look" tutorial on how to do this; ask if you don't know where it is). Then, render the 24p to 50i and Vegas will insert a field every half second and it will look great. Or, speed up the 24p by 4% (along with the audio, without pitching it) and you can do it without adding fields.

///d@